Introduce type declaration file for project after updating typescript dependency to 3.7.2.

.eslintignore

@@ -1,3 +1,4 @@
 demo/markdown-it.min.js
 demo/markdownlint-browser.js
 demo/markdownlint-browser.min.js
+example/typescript/type-check.js

doc/CustomRules.md

@@ -34,13 +34,13 @@ module.exports = {
 };
 ```
 
-A rule is implemented as an `Object` with four required properties:
+A rule is implemented as an `Object` with one optional and four required properties:
 
-- `names` is an `Array` of `String` values that identify the rule in output messages and config.
-- `description` is a `String` value that describes the rule in output messages.
+- `names` is a required `Array` of `String` values that identify the rule in output messages and config.
+- `description` is a required `String` value that describes the rule in output messages.
 - `information` is an optional (absolute) `URL` of a link to more information about the rule.
-- `tags` is an `Array` of `String` values that groups related rules for easier customization.
-- `function` is a synchronous `Function` that implements the rule and is passed two parameters:
+- `tags` is a required `Array` of `String` values that groups related rules for easier customization.
+- `function` is a required synchronous `Function` that implements the rule and is passed two parameters:
   - `params` is an `Object` with properties that describe the content being analyzed:
     - `name` is a `String` that identifies the input file/string.
     - `tokens` is an `Array` of [`markdown-it` `Token` objects](https://markdown-it.github.io/markdown-it/#Token)
@@ -48,7 +48,7 @@ A rule is implemented as an `Object` with four required properties:
     - `lines` is an `Array` of `String` values corresponding to the lines of the input file/string.
     - `frontMatterLines` is an `Array` of `String` values corresponding to any front matter (not present in `lines`).
     - `config` is an `Object` corresponding to the rule's entry in `options.config` (if present).
-  - `onError` is a function that takes a single `Object` parameter with one required and three optional properties:
+  - `onError` is a function that takes a single `Object` parameter with one required and four optional properties:
     - `lineNumber` is a required `Number` specifying the 1-based line number of the error.
     - `details` is an optional `String` with information about what caused the error.
     - `context` is an optional `String` with relevant text surrounding the error location.

example/typescript/.gitignore

@@ -0,0 +1 @@
+type-check.js

example/typescript/tsconfig.json

@@ -0,0 +1,11 @@
+{
+  "compilerOptions": {
+    "target": "es5",                          /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017', 'ES2018', 'ES2019' or 'ESNEXT'. */
+    "module": "commonjs",                     /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', or 'ESNext'. */
+    "strict": true,                           /* Enable all strict type-checking options. */
+    "noUnusedLocals": true,                   /* Report errors on unused locals. */
+    "noUnusedParameters": true,               /* Report errors on unused parameters. */
+    "esModuleInterop": true,                  /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies 'allowSyntheticDefaultImports'. */
+    "forceConsistentCasingInFileNames": true  /* Disallow inconsistently-cased references to the same file. */
+  }
+}

example/typescript/type-check.ts

@@ -0,0 +1,142 @@
+// Attempt to validate all the type declarations in markdownlint.d.ts
+
+import markdownlint from "../..";
+
+const assert = require("assert");
+const { URL } = require("url");
+const markdownlintJsonPath = "../../.markdownlint.json";
+
+function assertConfiguration(config: markdownlint.Configuration) {
+  assert(!!config);
+  assert.equal(config["line-length"], false);
+  assert.deepEqual(config["no-inline-html"], {
+    "allowed_elements": [
+      "a"
+    ]
+  });
+  // config assignment is covered by markdownlint.Options
+}
+
+function assertConfigurationCallback(err: Error | null, config?: markdownlint.Configuration) {
+  assert(!err);
+  config && assertConfiguration(config);
+}
+
+function assertLintResults(results: markdownlint.LintResults) {
+  assert(!!results);
+  assert.equal(results["string"].length, 1);
+  assert.equal(results["string"][0].lineNumber, 1);
+  assert.deepEqual(results["string"][0].ruleNames, [ "MD047", "single-trailing-newline" ]);
+  assert.equal(results["string"][0].ruleDescription, "Files should end with a single newline character");
+  assert.equal(results["string"][0].ruleInformation.replace(/v\d+\.\d+\.\d+/, "v0.0.0"), "https://github.com/DavidAnson/markdownlint/blob/v0.0.0/doc/Rules.md#md047");
+  assert.equal(results["string"][0].errorDetail, null);
+  assert.equal(results["string"][0].errorContext, null);
+  assert.deepEqual(results["string"][0].errorRange, [ 9, 1 ]);
+  assert(!!results["string"][0].fixInfo);
+  assert.equal(results["string"][0].fixInfo.editColumn, 10);
+  assert(!results["string"][0].fixInfo.deleteCount);
+  assert.equal(results["string"][0].fixInfo.insertText, "\n");
+  assert.equal(results["../bad.md"].length, 2);
+  results = {
+    "key": [
+      {
+        "lineNumber": 1,
+        "ruleNames": [ "rule", "names" ],
+        "ruleDescription": "description",
+        "ruleInformation": "https://example.com/ruleInformation",
+        "errorDetail": "detail",
+        "errorContext": "context",
+        "errorRange": [ 1, 2 ],
+        "fixInfo": {
+          "editColumn": 1,
+          "deleteCount": 1,
+          "insertText": "text"
+        }
+      }
+    ]
+  };
+}
+
+function assertLintResultsCallback(err: Error | null, results?: markdownlint.LintResults) {
+  assert(!err);
+  results && assertLintResults(results);
+}
+
+assertConfiguration(markdownlint.readConfigSync(markdownlintJsonPath));
+assertConfiguration(markdownlint.readConfigSync(markdownlintJsonPath, [ JSON.parse ]));
+
+// The following call is valid, but disallowed because TypeScript does not
+// currently propagate {ConfigurationParser[] | null} into the .d.ts file.
+// markdownlint.readConfig(markdownlintJsonPath, null, assertConfigCallback);
+markdownlint.readConfig(markdownlintJsonPath, [ JSON.parse ], assertConfigurationCallback);
+
+let options: markdownlint.Options;
+options = {
+  "files": [ "../bad.md" ],
+  "strings": {
+    "string": "# Heading"
+  },
+  "config": {
+    "no-missing-space-atx": false,
+    "no-hard-tabs": {
+      "code_blocks": true
+    }
+  },
+  "customRules": undefined,
+  "frontMatter": /---/,
+  "handleRuleFailures": false,
+  "noInlineConfig": false,
+  "resultVersion": 3,
+  "markdownItPlugins": [ [ require("markdown-it-sub") ] ]
+};
+
+assertLintResults(markdownlint.sync(options));
+markdownlint(options, assertLintResultsCallback);
+
+options.files = "../bad.md";
+assertLintResults(markdownlint.sync(options));
+markdownlint(options, assertLintResultsCallback);
+
+const testRule = {
+  "names": [ "test-rule" ],
+  "description": "Test rule",
+  "information": new URL("https://example.com/test-rule"),
+  "tags": [ "test-tag" ],
+  "function": function rule(params: markdownlint.RuleParams, onError: markdownlint.RuleOnError) {
+    assert(!!params);
+    assert(!!onError);
+    let ruleParams: markdownlint.RuleParams;
+    ruleParams = {
+      "name": "name",
+      "tokens": <markdownlint.MarkdownItToken[]>[],
+      "lines": [
+        "one",
+        "two"
+      ],
+      "frontMatterLines": [
+        "three"
+      ],
+      "config": options.config
+    };
+    assert(ruleParams);
+    let ruleOnErrorInfo: markdownlint.RuleOnErrorInfo;
+    ruleOnErrorInfo = {
+      "lineNumber": 1,
+      "details": "details",
+      "context": "context",
+      "range": [ 1, 2 ],
+      "fixInfo": {
+        "lineNumber": 1,
+        "editColumn": 1,
+        "deleteCount": 1,
+        "insertText": "text"
+      }
+    };
+    assert(ruleOnErrorInfo);
+    false && onError(ruleOnErrorInfo);
+  }
+};
+
+options.customRules = [ testRule ];
+assertLintResults(markdownlint.sync(options));
+markdownlint(options, assertLintResultsCallback);

lib/markdownlint.d.ts

@@ -0,0 +1,343 @@
+export = markdownlint;
+/**
+ * Lint specified Markdown files.
+ *
+ * @param {Options} options Configuration options.
+ * @param {LintCallback} callback Callback (err, result) function.
+ * @returns {void}
+ */
+declare function markdownlint(options: Options, callback: LintCallback): void;
+declare namespace markdownlint {
+    export { markdownlintSync as sync, readConfig, readConfigSync, RuleFunction, RuleParams, MarkdownItToken, RuleOnError, RuleOnErrorInfo, RuleOnErrorFixInfo, Rule, Options, Plugin, ToStringCallback, LintResults, LintError, FixInfo, LintCallback, Configuration, RuleConfiguration, ConfigurationParser, ReadConfigCallback };
+}
+/**
+ * Configuration options.
+ */
+type Options = {
+    /**
+     * Files to lint.
+     */
+    files?: string | string[];
+    /**
+     * Strings to lint.
+     */
+    strings?: {
+        [x: string]: string;
+    };
+    /**
+     * Configuration object.
+     */
+    config?: {
+        [x: string]: any;
+    };
+    /**
+     * Custom rules.
+     */
+    customRules?: Rule | Rule[];
+    /**
+     * Front matter pattern.
+     */
+    frontMatter?: RegExp;
+    /**
+     * True to catch exceptions.
+     */
+    handleRuleFailures?: boolean;
+    /**
+     * True to ignore HTML directives.
+     */
+    noInlineConfig?: boolean;
+    /**
+     * Results object version.
+     */
+    resultVersion?: number;
+    /**
+     * Additional plugins.
+     */
+    markdownItPlugins?: any[][];
+};
+/**
+ * Called with the result of the lint operation.
+ */
+type LintCallback = (err: Error, results?: {
+    [x: string]: LintError[];
+}) => void;
+/**
+ * Lint specified Markdown files synchronously.
+ *
+ * @param {Options} options Configuration options.
+ * @returns {LintResults} Results object.
+ */
+declare function markdownlintSync(options: Options): {
+    [x: string]: LintError[];
+};
+/**
+ * Read specified configuration file.
+ *
+ * @param {string} file Configuration file name.
+ * @param {ConfigurationParser[] | null} parsers Parsing function(s).
+ * @param {ReadConfigCallback} callback Callback (err, result) function.
+ * @returns {void}
+ */
+declare function readConfig(file: string, parsers: ConfigurationParser[], callback: ReadConfigCallback): void;
+/**
+ * Read specified configuration file synchronously.
+ *
+ * @param {string} file Configuration file name.
+ * @param {ConfigurationParser[]} [parsers] Parsing function(s).
+ * @returns {Configuration} Configuration object.
+ */
+declare function readConfigSync(file: string, parsers?: ConfigurationParser[]): {
+    [x: string]: any;
+};
+/**
+ * Function to implement rule logic.
+ */
+type RuleFunction = (params: RuleParams, onError: RuleOnError) => void;
+/**
+ * Rule parameters.
+ */
+type RuleParams = {
+    /**
+     * File/string name.
+     */
+    name: string;
+    /**
+     * markdown-it token objects.
+     */
+    tokens: MarkdownItToken[];
+    /**
+     * File/string lines.
+     */
+    lines: string[];
+    /**
+     * Front matter lines.
+     */
+    frontMatterLines: string[];
+    /**
+     * Rule configuration.
+     */
+    config: any;
+};
+/**
+ * Markdown-It token.
+ */
+type MarkdownItToken = {
+    /**
+     * HTML attributes.
+     */
+    attrs: string[][];
+    /**
+     * Block-level token.
+     */
+    block: boolean;
+    /**
+     * Child nodes.
+     */
+    children: MarkdownItToken[];
+    /**
+     * Tag contents.
+     */
+    content: string;
+    /**
+     * Ignore element.
+     */
+    hidden: boolean;
+    /**
+     * Fence info.
+     */
+    info: string;
+    /**
+     * Nesting level.
+     */
+    level: number;
+    /**
+     * Beginning/ending line numbers.
+     */
+    map: number[];
+    /**
+     * Markup text.
+     */
+    markup: string;
+    /**
+     * Arbitrary data.
+     */
+    meta: any;
+    /**
+     * Level change.
+     */
+    nesting: number;
+    /**
+     * HTML tag name.
+     */
+    tag: string;
+    /**
+     * Token type.
+     */
+    type: string;
+};
+/**
+ * Error-reporting callback.
+ */
+type RuleOnError = (onErrorInfo: RuleOnErrorInfo) => void;
+/**
+ * Fix information for RuleOnError callback.
+ */
+type RuleOnErrorInfo = {
+    /**
+     * Line number (1-based).
+     */
+    lineNumber: number;
+    /**
+     * Details about the error.
+     */
+    details?: string;
+    /**
+     * Context for the error.
+     */
+    context?: string;
+    /**
+     * Column number (1-based) and length.
+     */
+    range?: number[];
+    /**
+     * Fix information.
+     */
+    fixInfo?: RuleOnErrorFixInfo;
+};
+/**
+ * Fix information for RuleOnErrorInfo.
+ */
+type RuleOnErrorFixInfo = {
+    /**
+     * Line number (1-based).
+     */
+    lineNumber?: number;
+    /**
+     * Column of the fix (1-based).
+     */
+    editColumn?: number;
+    /**
+     * Count of characters to delete.
+     */
+    deleteCount?: number;
+    /**
+     * Text to insert (after deleting).
+     */
+    insertText?: string;
+};
+/**
+ * Rule definition.
+ */
+type Rule = {
+    /**
+     * Rule name(s).
+     */
+    names: string[];
+    /**
+     * Rule description.
+     */
+    description: string;
+    /**
+     * Link to more information.
+     */
+    information?: URL;
+    /**
+     * Rule tag(s).
+     */
+    tags: string[];
+    /**
+     * Rule implementation.
+     */
+    function: RuleFunction;
+};
+/**
+ * markdown-it plugin.
+ */
+type Plugin = any[];
+/**
+ * Function to pretty-print lint results.
+ */
+type ToStringCallback = (ruleAliases?: boolean) => string;
+/**
+ * Lint results (for resultVersion 3).
+ */
+type LintResults = {
+    [x: string]: LintError[];
+};
+/**
+ * Lint error.
+ */
+type LintError = {
+    /**
+     * Line number (1-based).
+     */
+    lineNumber: number;
+    /**
+     * Rule name(s).
+     */
+    ruleNames: string[];
+    /**
+     * Rule description.
+     */
+    ruleDescription: string;
+    /**
+     * Link to more information.
+     */
+    ruleInformation: string;
+    /**
+     * Detail about the error.
+     */
+    errorDetail: string;
+    /**
+     * Context for the error.
+     */
+    errorContext: string;
+    /**
+     * Column number (1-based) and length.
+     */
+    errorRange: number[];
+    /**
+     * Fix information.
+     */
+    fixInfo: FixInfo;
+};
+/**
+ * Fix information.
+ */
+type FixInfo = {
+    /**
+     * Column of the fix (1-based).
+     */
+    editColumn?: number;
+    /**
+     * Count of characters to delete.
+     */
+    deleteCount?: number;
+    /**
+     * Text to insert (after deleting).
+     */
+    insertText?: string;
+};
+/**
+ * Configuration object for linting rules. For a detailed schema, see
+ * {@link ../schema/markdownlint-config-schema.json}.
+ */
+type Configuration = {
+    [x: string]: any;
+};
+/**
+ * Rule configuration.
+ */
+type RuleConfiguration = any;
+/**
+ * Parses a configuration string and returns a configuration object.
+ */
+type ConfigurationParser = (text: string) => {
+    [x: string]: any;
+};
+/**
+ * Called with the result of the readConfig operation.
+ */
+type ReadConfigCallback = (err: Error, config?: {
+    [x: string]: any;
+}) => void;

lib/markdownlint.js

@@ -615,8 +615,8 @@ function lintInput(options, synchronous, callback) {
 /**
  * Lint specified Markdown files.
  *
- * @param {Object} options Configuration options.
- * @param {Function} callback Callback (err, result) function.
+ * @param {Options} options Configuration options.
+ * @param {LintCallback} callback Callback (err, result) function.
  * @returns {void}
  */
 function markdownlint(options, callback) {
@@ -626,8 +626,8 @@ function markdownlint(options, callback) {
 /**
  * Lint specified Markdown files synchronously.
  *
- * @param {Object} options Configuration options.
- * @returns {Object} Result object.
+ * @param {Options} options Configuration options.
+ * @returns {LintResults} Results object.
  */
 function markdownlintSync(options) {
   let results = null;
@@ -668,9 +668,9 @@ function parseConfiguration(name, content, parsers) {
 /**
  * Read specified configuration file.
  *
- * @param {String} file Configuration file name/path.
- * @param {Array} [parsers] Optional parsing function(s).
- * @param {Function} callback Callback (err, result) function.
+ * @param {string} file Configuration file name.
+ * @param {ConfigurationParser[] | null} parsers Parsing function(s).
+ * @param {ReadConfigCallback} callback Callback (err, result) function.
  * @returns {void}
  */
 function readConfig(file, parsers, callback) {
@@ -711,9 +711,9 @@ function readConfig(file, parsers, callback) {
 /**
  * Read specified configuration file synchronously.
  *
- * @param {String} file Configuration file name/path.
- * @param {Array} [parsers] Optional parsing function(s).
- * @returns {Object} Configuration object.
+ * @param {string} file Configuration file name.
+ * @param {ConfigurationParser[]} [parsers] Parsing function(s).
+ * @returns {Configuration} Configuration object.
  */
 function readConfigSync(file, parsers) {
   // Read file
@@ -743,3 +743,185 @@ markdownlint.sync = markdownlintSync;
 markdownlint.readConfig = readConfig;
 markdownlint.readConfigSync = readConfigSync;
 module.exports = markdownlint;
+
+// Type declarations
+
+/**
+ * Function to implement rule logic.
+ *
+ * @callback RuleFunction
+ * @param {RuleParams} params Rule parameters.
+ * @param {RuleOnError} onError Error-reporting callback.
+ * @returns {void}
+ */
+
+/**
+ * Rule parameters.
+ *
+ * @typedef {Object} RuleParams
+ * @property {string} name File/string name.
+ * @property {MarkdownItToken[]} tokens markdown-it token objects.
+ * @property {string[]} lines File/string lines.
+ * @property {string[]} frontMatterLines Front matter lines.
+ * @property {RuleConfiguration} config Rule configuration.
+ */
+
+/**
+ * Markdown-It token.
+ *
+ * @typedef {Object} MarkdownItToken
+ * @property {string[][]} attrs HTML attributes.
+ * @property {boolean} block Block-level token.
+ * @property {MarkdownItToken[]} children Child nodes.
+ * @property {string} content Tag contents.
+ * @property {boolean} hidden Ignore element.
+ * @property {string} info Fence info.
+ * @property {number} level Nesting level.
+ * @property {number[]} map Beginning/ending line numbers.
+ * @property {string} markup Markup text.
+ * @property {Object} meta Arbitrary data.
+ * @property {number} nesting Level change.
+ * @property {string} tag HTML tag name.
+ * @property {string} type Token type.
+ */
+
+/**
+ * Error-reporting callback.
+ *
+ * @callback RuleOnError
+ * @param {RuleOnErrorInfo} onErrorInfo Error information.
+ * @returns {void}
+ */
+
+/**
+ * Fix information for RuleOnError callback.
+ *
+ * @typedef {Object} RuleOnErrorInfo
+ * @property {number} lineNumber Line number (1-based).
+ * @property {string} [details] Details about the error.
+ * @property {string} [context] Context for the error.
+ * @property {number[]} [range] Column number (1-based) and length.
+ * @property {RuleOnErrorFixInfo} [fixInfo] Fix information.
+ */
+
+/**
+ * Fix information for RuleOnErrorInfo.
+ *
+ * @typedef {Object} RuleOnErrorFixInfo
+ * @property {number} [lineNumber] Line number (1-based).
+ * @property {number} [editColumn] Column of the fix (1-based).
+ * @property {number} [deleteCount] Count of characters to delete.
+ * @property {string} [insertText] Text to insert (after deleting).
+ */
+
+/**
+ * Rule definition.
+ *
+ * @typedef {Object} Rule
+ * @property {string[]} names Rule name(s).
+ * @property {string} description Rule description.
+ * @property {URL} [information] Link to more information.
+ * @property {string[]} tags Rule tag(s).
+ * @property {RuleFunction} function Rule implementation.
+ */
+
+/**
+ * Configuration options.
+ *
+ * @typedef {Object} Options
+ * @property {string[] | string} [files] Files to lint.
+ * @property {Object.<string, string>} [strings] Strings to lint.
+ * @property {Configuration} [config] Configuration object.
+ * @property {Rule[] | Rule} [customRules] Custom rules.
+ * @property {RegExp} [frontMatter] Front matter pattern.
+ * @property {boolean} [handleRuleFailures] True to catch exceptions.
+ * @property {boolean} [noInlineConfig] True to ignore HTML directives.
+ * @property {number} [resultVersion] Results object version.
+ * @property {Plugin[]} [markdownItPlugins] Additional plugins.
+ */
+
+/**
+ * markdown-it plugin.
+ *
+ * @typedef {Array} Plugin
+ */
+
+/**
+ * Function to pretty-print lint results.
+ *
+ * @callback ToStringCallback
+ * @param {boolean} [ruleAliases] True to use rule aliases.
+ * @returns {string}
+ */
+
+/**
+ * Lint results (for resultVersion 3).
+ *
+ * @typedef {Object.<string, LintError[]>} LintResults
+ */
+// The following should be part of the LintResults typedef, but that causes
+// TypeScript to "forget" about the string map.
+// * @property {ToStringCallback} toString String representation.
+// https://github.com/microsoft/TypeScript/issues/34911
+
+/**
+ * Lint error.
+ *
+ * @typedef {Object} LintError
+ * @property {number} lineNumber Line number (1-based).
+ * @property {string[]} ruleNames Rule name(s).
+ * @property {string} ruleDescription Rule description.
+ * @property {string} ruleInformation Link to more information.
+ * @property {string} errorDetail Detail about the error.
+ * @property {string} errorContext Context for the error.
+ * @property {number[]} errorRange Column number (1-based) and length.
+ * @property {FixInfo} fixInfo Fix information.
+ */
+
+/**
+ * Fix information.
+ *
+ * @typedef {Object} FixInfo
+ * @property {number} [editColumn] Column of the fix (1-based).
+ * @property {number} [deleteCount] Count of characters to delete.
+ * @property {string} [insertText] Text to insert (after deleting).
+ */
+
+/**
+ * Called with the result of the lint operation.
+ *
+ * @callback LintCallback
+ * @param {Error | null} err Error object or null.
+ * @param {LintResults} [results] Lint results.
+ * @returns {void}
+ */
+
+/**
+ * Configuration object for linting rules. For a detailed schema, see
+ * {@link ../schema/markdownlint-config-schema.json}.
+ *
+ * @typedef {Object.<string, RuleConfiguration>} Configuration
+ */
+
+/**
+ * Rule configuration object.
+ *
+ * @typedef {boolean | Object} RuleConfiguration Rule configuration.
+ */
+
+/**
+ * Parses a configuration string and returns a configuration object.
+ *
+ * @callback ConfigurationParser
+ * @param {string} text Configuration string.
+ * @returns {Configuration}
+ */
+
+/**
+ * Called with the result of the readConfig operation.
+ *
+ * @callback ReadConfigCallback
+ * @param {Error | null} err Error object or null.
+ * @param {Configuration} [config] Configuration object.
+ * @returns {void}
+ */

package.json

@@ -3,6 +3,7 @@
   "version": "0.17.2",
   "description": "A Node.js style checker and lint tool for Markdown/CommonMark files.",
   "main": "lib/markdownlint.js",
+  "types": "lib/markdownlint.d.ts",
   "author": "David Anson (https://dlaa.me/)",
   "license": "MIT",
   "homepage": "https://github.com/DavidAnson/markdownlint",
@@ -14,11 +15,13 @@
   "scripts": {
     "test": "nodeunit test/markdownlint-test.js",
     "test-cover": "nyc --check-coverage --skip-full node_modules/nodeunit/bin/nodeunit test/markdownlint-test.js",
+    "test-declaration": "cd example/typescript && tsc && node type-check.js",
     "test-extra": "nodeunit test/markdownlint-test-extra.js",
     "debug": "node debug node_modules/nodeunit/bin/nodeunit",
     "lint": "eslint lib helpers test schema && eslint --env browser --global markdownit --global markdownlint --rule \"no-unused-vars: 0, no-extend-native: 0, max-statements: 0, no-console: 0, no-var: 0\" demo && eslint --rule \"no-console: 0, no-invalid-this: 0, no-shadow: 0, object-property-newline: 0\" example",
-    "ci": "npm run test && npm run lint && npm run test-cover",
+    "ci": "npm run test && npm run lint && npm run test-cover && npm run test-declaration",
     "build-config-schema": "node schema/build-config-schema.js",
+    "build-declaration": "tsc --allowJs --declaration --outDir declaration --resolveJsonModule lib/markdownlint.js && cpy declaration/lib/markdownlint.d.ts lib && rimraf declaration",
     "build-demo": "cpy node_modules/markdown-it/dist/markdown-it.min.js demo && cd demo && rimraf markdownlint-browser.* && cpy file-header.js . --rename=markdownlint-browser.js && tsc --allowJs --resolveJsonModule --outDir ../lib-es3 ../lib/markdownlint.js && cpy ../helpers/package.json ../lib-es3/helpers && browserify ../lib-es3/lib/markdownlint.js --standalone markdownlint >> markdownlint-browser.js && uglifyjs markdownlint-browser.js --compress --mangle --comments --output markdownlint-browser.min.js",
     "build-example": "npm install --no-save --ignore-scripts grunt grunt-cli gulp through2",
     "example": "cd example && node standalone.js && grunt markdownlint --force && gulp markdownlint"
@@ -46,7 +49,7 @@
     "rimraf": "~3.0.0",
     "toml": "~3.0.0",
     "tv4": "~1.3.0",
-    "typescript": "~3.6.3",
+    "typescript": "~3.7.2",
     "uglify-js": "~3.6.0"
   },
   "keywords": [

test/markdownlint-test.js

@@ -247,6 +247,7 @@ module.exports.resultFormattingV0 = function resultFormattingV0(test) {
       "./test/first_heading_bad_atx.md: 1: MD002" +
       " First heading should be a top level heading";
     test.equal(actualMessage, expectedMessage, "Incorrect message (name).");
+    // @ts-ignore
     actualMessage = actualResult.toString(true);
     expectedMessage =
       "./test/atx_heading_spacing.md: 3: first-heading-h1" +
@@ -2872,6 +2873,7 @@ module.exports.customRulesV0 = function customRulesV0(test) {
       "./test/custom-rules.md: 7: letters-E-X" +
       " Rule that reports an error for lines with the letters 'EX'";
     test.equal(actualMessage, expectedMessage, "Incorrect message (name).");
+    // @ts-ignore
     actualMessage = actualResult.toString(true);
     expectedMessage =
       "./test/custom-rules.md: 12: any-blockquote" +