ESLint-browserify

API

The eslint global variable has a Linter constructor.

const linter = new eslint.Linter();

Linter

The Linter instance does the actual evaluation of the JavaScript code. It parses and reports on the code.

Linter#verify

The most important method on Linter is verify(), which initiates linting of the given text. This method accepts three arguments:

• code - the source code to lint (a string).
• config - a configuration object or an array of configuration objects.

You can call verify() like this:

const linter = new eslint.Linter();

const messages = linter.verify(
	"var foo",
	{
		rules: {
			semi: 2,
		},
	},
);

The verify() method returns an array of objects containing information about the linting warnings and errors. Here's an example:

[
	{
		fatal: false,
		ruleId: "semi",
		severity: 2,
		line: 1,
		column: 8,
		message: "Missing semicolon.",
		fix: {
			range: [7, 7],
			text: ";",
		},
	},
];

The information available for each linting message is:

• column - the column on which the error occurred.
• fatal - usually omitted, but will be set to true if there's a parsing error (not related to a rule).
• line - the line on which the error occurred.
• message - the message that should be output.
• messageId - the ID of the message used to generate the message (this property is omitted if the rule does not use message IDs).
• ruleId - the ID of the rule that triggered the messages (or null if fatal is true).
• severity - either 1 or 2, depending on your configuration.
• endColumn - the end column of the range on which the error occurred (this property is omitted if it's not range).
• endLine - the end line of the range on which the error occurred (this property is omitted if it's not range).
• fix - an object describing the fix for the problem (this property is omitted if no fix is available).
• suggestions - an array of objects describing possible lint fixes for editors to programmatically enable.

Linter#verifyAndFix

This method is similar to verify except that it also runs autofixing logic, similar to the --fix flag on the command line. The result object will contain the autofixed code, along with any remaining linting messages for the code that were not autofixed.

const linter = new eslint.Linter();

const messages = linter.verifyAndFix("var foo", {
	rules: {
		semi: 2,
	},
});

Output object from this method:

{
    fixed: true,
    output: "var foo;",
    messages: []
}

The information available is:

• fixed - true, if the code was fixed.
• output - fixed code text (might be the same as input if no fixes were applied).
• messages - collection of all messages for the given code (It has the same information as explained above under verify block).