disallow invalid regular expression strings in RegExp constructors (no-invalid-regexp)

The "extends": "eslint:recommended" property in a configuration file enables this rule.

An invalid pattern in a regular expression literal is a SyntaxError when the code is parsed, but an invalid string in RegExp constructors throws a SyntaxError only when the code is executed.

Rule Details

This rule disallows invalid regular expression strings in RegExp constructors.

Examples of incorrect code for this rule:

/*eslint no-invalid-regexp: "error"*/

RegExp('[')

RegExp('.', 'z')

new RegExp('\\')

Examples of correct code for this rule:

/*eslint no-invalid-regexp: "error"*/

RegExp('.')

new RegExp

this.RegExp('[')

Environments

ECMAScript 6 adds the following flag arguments to the RegExp constructor:

• "u" (unicode)
• "y" (sticky)

You can enable these to be recognized as valid by setting the ECMAScript version to 6 in your ESLint configuration.

If you want to allow additional constructor flags for any reason, you can specify them using an allowConstructorFlags option in .eslintrc. These flags will then be ignored by the rule regardless of the ecmaVersion setting.

Options

This rule has an object option for exceptions:

• "allowConstructorFlags" is an array of flags

allowConstructorFlags

Examples of correct code for this rule with the { "allowConstructorFlags": ["u", "y"] } option:

/*eslint no-invalid-regexp: ["error", { "allowConstructorFlags": ["u", "y"] }]*/

new RegExp('.', 'y')

new RegExp('.', 'yu')

Further Reading

• Annotated ES5 §7.8.5 - Regular Expression Literals

Version

This rule was introduced in ESLint 0.1.4.

Resources

• Rule source
• Documentation source