js-lint.js

'use strict';

const gulp = require('gulp');
const $ = require('gulp-load-plugins')();
const through2 = require('through2').obj;
const fs = require('fs');
const multipipe = require('multipipe');

//	function isFixed(file) {
//		return file.eslint != null && file.eslint.fixed;  // has ESLint fixed the file contents?
//	}

module.exports = function(options) {

	return function() {

		let eslintResults = {};
		let cacheFilePath = options.cacheFilePath;

		try {
			eslintResults = JSON.parse(fs.readFileSync(cacheFilePath));
		} catch (e) {
		}

		return gulp.src(options.src, {read: false})
			.pipe($.if(
				function(file) {
					return eslintResults[file.path] && eslintResults[file.path].mtime == file.stat.mtime.toJSON();
				},
				through2(function(file, enc, callback) {
					file.eslint = eslintResults[file.path].eslint;
					callback(null, file);
				}),
				multipipe(
					through2(function(file, enc, callback) {
						file.contents = fs.readFileSync(file.path);
						callback(null, file);
					}),
					$.eslint({ fix: true }),  // https://stackoverflow.com/a/37108027/6263942
//	how to use?		$.eslint.format(),
//	how to use?		$.if(isFixed, gulp.dest(options.dest)),
					$.eslint.failAfterError(),
					through2(function(file, enc, callback) {
						eslintResults[file.path] = {
							eslint: file.eslint,
							mtime: file.stat.mtime,
						};
						callback(null, file);
					})
				)
			))
			.on('end', function() {
				fs.writeFileSync(cacheFilePath, JSON.stringify((eslintResults)));
			})
			.pipe($.eslint.format());
	};

};