Drop lodash

package.json

@@ -34,7 +34,7 @@
     "axios": "^0.19.2",
     "better-ajv-errors": "^0.6.7",
     "consola": "^2.11.3",
-    "lodash": "^4.17.15",
+    "fast-escape-regexp": "^1.0.1",
     "tldts": "^5.6.10",
     "yargs": "^15.3.0"
   }

src/filter.js

@@ -1,4 +1,3 @@
-const _ = require('lodash');
 const { FiltersDownloader } = require('@adguard/filters-downloader');
 const utils = require('./utils');
 const ruleUtils = require('./rule');
@@ -12,7 +11,7 @@ const ruleUtils = require('./rule');
  */
 async function downloadAll(sources) {
     let list = [];
-    if (_.isEmpty(sources)) {
+    if (!sources?.length) {
         return list;
     }
 
@@ -36,12 +35,12 @@ async function downloadAll(sources) {
  */
 async function prepareWildcards(rules, sources) {
     let list = [];
-    if (!_.isEmpty(rules)) {
+    if (rules.length > 0) {
         list = list.concat(rules);
     }
     const loadedList = await downloadAll(sources);
     list = list.concat(loadedList);
-    list = _.compact(_.uniq(list));
+    list = Array.from(new Set(list)).filter(Boolean); // remove duplicates
 
     return list.map((str) => new utils.Wildcard(str));
 }

src/index.js

@@ -1,4 +1,3 @@
-const _ = require('lodash');
 const consola = require('consola');
 const config = require('./configuration');
 const compileSource = require('./compile-source');
@@ -18,16 +17,16 @@ function prepareHeader(configuration) {
         `! Title: ${configuration.name}`,
     ];
 
-    if (!_.isEmpty(configuration.description)) {
+    if (configuration.description?.length) {
         lines.push(`! Description: ${configuration.description}`);
     }
-    if (!_.isEmpty(configuration.version)) {
+    if (configuration.version?.length) {
         lines.push(`! Version: ${configuration.version}`);
     }
-    if (!_.isEmpty(configuration.homepage)) {
+    if (configuration.homepage?.length) {
         lines.push(`! Homepage: ${configuration.homepage}`);
     }
-    if (!_.isEmpty(configuration.license)) {
+    if (configuration.license?.length) {
         lines.push(`! License: ${configuration.license}`);
     }
 
@@ -55,7 +54,7 @@ function prepareSourceHeader(source) {
         '!',
     ];
 
-    if (!_.isEmpty(source.name)) {
+    if (source.name.length > 0) {
         lines.push(`! Source name: ${source.name}`);
     }
     lines.push(`! Source: ${source.source}`);

src/rule.js

@@ -1,4 +1,3 @@
-const _ = require('lodash');
 const { domainToASCII } = require('url');
 const utils = require('./utils');
 
@@ -18,26 +17,26 @@ const nonAsciiRegexp = /[^\x00-\x7F]/;
 * @returns {Boolean} true if rule is a comment
 */
 function isComment(ruleText) {
-    return _.startsWith(ruleText, '!')
-        || _.startsWith(ruleText, '# ')
+    return ruleText.startsWith('!')
+        || ruleText.startsWith('# ')
         || ruleText === '#'
-        || _.startsWith(ruleText, '####');
+        || ruleText.startsWith('####');
 }
 
 /**
  * @param {String} ruleText - rule to check
  * @returns {Boolean} true if the rule is "allowing"
  */
 function isAllowRule(ruleText) {
-    return _.startsWith(ruleText, '@@');
+    return ruleText.startsWith('@@');
 }
 
 /**
  * @param {String} rule - rule to check
  * @returns {Boolean} true if the rule is just the domain name
  */
 function isJustDomain(ruleText) {
-    return _.includes(ruleText, '.')
+    return ruleText.includes('.')
         && domainRegex.test(ruleText);
 }
 
@@ -100,7 +99,7 @@ function parseRuleTokens(ruleText) {
     };
 
     let startIndex = 0;
-    if (_.startsWith(ruleText, '@@')) {
+    if (ruleText.startsWith('@@')) {
         tokens.whitelist = true;
         startIndex = 2;
     }
@@ -113,8 +112,8 @@ function parseRuleTokens(ruleText) {
     tokens.pattern = ruleText.substring(startIndex);
 
     // Avoid parsing options inside of a regex rule
-    if (_.startsWith(tokens.pattern, '/')
-        && _.endsWith(tokens.pattern, '/')
+    if (tokens.pattern.startsWith('/')
+        && tokens.pattern.endsWith('/')
         && tokens.pattern.indexOf('replace=') === -1) {
         return tokens;
     }
@@ -150,12 +149,12 @@ function parseRuleTokens(ruleText) {
  * @throws {TypeError} thrown if it is not a valid /etc/hosts rule
  */
 function loadEtcHostsRuleProperties(ruleText) {
-    let rule = _.trim(ruleText);
+    let rule = ruleText.trim();
     if (rule.indexOf('#') > 0) {
         rule = rule.substring(0, rule.indexOf('#'));
     }
 
-    const [, ...hostnames] = _.trim(rule).split(/\s+/);
+    const [, ...hostnames] = rule.trim().split(/\s+/);
     if (hostnames.length < 1) {
         throw new TypeError(`Invalid /etc/hosts rule: ${ruleText}`);
     }
@@ -171,7 +170,7 @@ function loadEtcHostsRuleProperties(ruleText) {
  * @typedef {Object} AdblockRule
  * @property {String} ruleText - original rule text
  * @property {String} pattern - matching pattern
- * @property {Array<{{name: string, value: string}}>} options - list of rule modifiers
+ * @property {Array<{name: string, value: string}>} [options] - list of rule modifiers
  * @property {Boolean} whitelist - whether this is an exception rule or not
  * @property {String} hostname - hostname can only be extracted from the rules
  *                               that look like `||[a-z0-9-.]^.*`
@@ -197,7 +196,7 @@ function extractHostname(pattern) {
  * @returns {AdblockRule} - rule properties
  */
 function loadAdblockRuleProperties(ruleText) {
-    const tokens = parseRuleTokens(_.trim(ruleText));
+    const tokens = parseRuleTokens(ruleText.trim());
     const rule = {
         ruleText,
         pattern: tokens.pattern,
@@ -213,7 +212,7 @@ function loadAdblockRuleProperties(ruleText) {
 
             // eslint-disable-next-line no-restricted-syntax
             for (const option of optionParts) {
-                const parts = _.split(option, '=', 2);
+                const parts = option.split('=', 2);
                 const name = parts[0];
                 const value = parts[1] ? parts[1] : null;
                 rule.options.push({
@@ -285,7 +284,7 @@ function adblockRuleToString(ruleProps) {
         ruleText = '@@';
     }
     ruleText += ruleProps.pattern;
-    if (!_.isEmpty(ruleProps.options)) {
+    if (ruleProps.options && ruleProps.options.length > 0) {
         ruleText += '$';
         for (let i = 0; i < ruleProps.options.length; i += 1) {
             const option = ruleProps.options[i];

src/transformations/compress.js

@@ -1,4 +1,3 @@
-const _ = require('lodash');
 const consola = require('consola');
 const ruleUtils = require('../rule');
 
@@ -71,7 +70,7 @@ function toAdblockRules(ruleText) {
     // try parsing an adblock rule and check if it can be compressed
     try {
         const props = ruleUtils.loadAdblockRuleProperties(ruleText);
-        if (props.hostname && !props.whitelist && _.isEmpty(props.options)) {
+        if (props.hostname && !props.whitelist && props.options.length === 0) {
             adblockRules.push({
                 ruleText,
                 canCompress: true,

src/transformations/deduplicate.js

@@ -1,4 +1,3 @@
-const _ = require('lodash');
 const consola = require('consola');
 const ruleUtils = require('../rule');
 
@@ -14,7 +13,7 @@ const ruleUtils = require('../rule');
  * @returns {Array<String>} "deduplicated" array of rules
  */
 function deduplicate(rules) {
-    if (_.isEmpty(rules)) {
+    if (rules.length === 0) {
         consola.info('Empty rules array, nothing to deduplicate');
         return rules;
     }
@@ -32,11 +31,11 @@ function deduplicate(rules) {
             rulesIndex[ruleText] = true;
         }
 
-        if (dup && !ruleUtils.isComment(ruleText) && !_.isEmpty(ruleText)) {
+        if (dup && !ruleUtils.isComment(ruleText) && ruleText.length > 0) {
             prevRuleRemoved = true;
             consola.debug(`Removing duplicate: ${ruleText}`);
             filtered.splice(iFiltered, 1);
-        } else if (prevRuleRemoved && (ruleUtils.isComment(ruleText) || _.isEmpty(ruleText))) {
+        } else if (prevRuleRemoved && (ruleUtils.isComment(ruleText) || ruleText.length === 0)) {
             // Remove preceding comments and empty lines
             consola.debug(`Removing a comment preceding duplicate: ${ruleText}`);
             filtered.splice(iFiltered, 1);

src/transformations/exclude.js

@@ -1,4 +1,3 @@
-const _ = require('lodash');
 const consola = require('consola');
 const filterUtils = require('../filter');
 
@@ -12,13 +11,13 @@ const filterUtils = require('../filter');
  * @returns {Promise<Array<String>>} filtered array of rules
  */
 async function exclude(rules, exclusions, exclusionsSources) {
-    if (_.isEmpty(exclusions) && _.isEmpty(exclusionsSources)) {
+    if ((!exclusions || exclusions.length === 0) && (!exclusionsSources || exclusionsSources.length === 0)) {
         // Nothing to filter here
         return rules;
     }
 
     const wildcards = await filterUtils.prepareWildcards(exclusions, exclusionsSources);
-    if (_.isEmpty(wildcards)) {
+    if (wildcards.length === 0) {
         return rules;
     }
     consola.info(`Filtering the list of rules using ${wildcards.length} exclusion rules`);

src/transformations/include.js

@@ -1,4 +1,3 @@
-const _ = require('lodash');
 const consola = require('consola');
 const filterUtils = require('../filter');
 
@@ -12,13 +11,13 @@ const filterUtils = require('../filter');
  * @returns {Promise<Array<String>>} filtered array of rules
  */
 async function include(rules, inclusions, inclusionsSources) {
-    if (_.isEmpty(inclusions) && _.isEmpty(inclusionsSources)) {
+    if ((!inclusions || inclusions.length === 0) && (!inclusionsSources || inclusionsSources.length === 0)) {
         // Nothing to filter here
         return rules;
     }
 
     const wildcards = await filterUtils.prepareWildcards(inclusions, inclusionsSources);
-    if (_.isEmpty(wildcards)) {
+    if (wildcards.length === 0) {
         return rules;
     }
     consola.info(`Filtering the list of rules using ${wildcards.length} inclusion rules`);

src/transformations/remove-modifiers.js

@@ -1,4 +1,3 @@
-const _ = require('lodash');
 const consola = require('consola');
 const ruleUtils = require('../rule');
 
@@ -15,7 +14,7 @@ function removeModifiers(rules) {
     let modifiedCount = 0;
     rules.forEach((rawRuleText) => {
         const ruleText = rawRuleText.trim();
-        if (_.isEmpty(ruleText) || ruleUtils.isComment(ruleText)) {
+        if (ruleText.length === 0 || ruleUtils.isComment(ruleText)) {
             filtered.push(ruleText);
             return;
         }

src/transformations/trim-lines.js

@@ -1,5 +1,4 @@
 const consola = require('consola');
-const _ = require('lodash');
 
 /**
  * This is a very simple transformation that removes leading and trailing spaces/tabs.
@@ -8,7 +7,7 @@ const _ = require('lodash');
  * @returns {Array<string>} filtered lines/rules
  */
 function trimLines(lines) {
-    const transformed = lines.map((line) => _.trim(line, ' \t'));
+    const transformed = lines.map((line) => line.replace(/^[ \t]+|[ \t]+$/g, ''));
     consola.info('Lines trimmed.');
     return transformed;
 }

src/transformations/validate.js

@@ -1,4 +1,3 @@
-const _ = require('lodash');
 const consola = require('consola');
 const tldts = require('tldts');
 const utils = require('../utils');
@@ -9,8 +8,6 @@ const DOMAIN_SEPARATOR = '^';
 const WILDCARD = '*';
 const WILDCARD_DOMAIN_PART = '*.';
 
-// TODO: Remove lodash from the project if possible
-
 /**
  * The list of modifiers that limit the rule for specific domains.
  */
@@ -91,7 +88,7 @@ function validEtcHostsRule(ruleText, allowIP) {
         consola.error(`Unexpected incorrect /etc/hosts rule: ${ruleText}: ${ex}`);
         return false;
     }
-    if (_.isEmpty(props.hostnames)) {
+    if (!props.hostnames?.length) {
         consola.info(`The rule has no hostnames: ${ruleText}`);
         return false;
     }
@@ -153,8 +150,8 @@ function validAdblockRule(ruleText, allowedIP) {
 
     // 3.1. Special case: regex rules
     // Do nothing with regex rules -- they may contain all kinds of special chars
-    if (_.startsWith(props.pattern, '/')
-        && _.endsWith(props.pattern, '/')) {
+    if (props.pattern.startsWith('/')
+        && props.pattern.endsWith('/')) {
         return true;
     }
 
@@ -163,8 +160,8 @@ function validAdblockRule(ruleText, allowedIP) {
     // *|^ -- special characters used by adblock-style rules
     // One more special case is rules starting with ://s
     let toTest = props.pattern;
-    if (_.startsWith(toTest, '://')) {
-        toTest = _.trimStart(toTest, '://');
+    if (toTest.startsWith('://')) {
+        toTest = toTest.replace('://', '');
     }
 
     const checkChars = /^[a-zA-Z0-9-.*|^]+$/.test(toTest);
@@ -183,7 +180,7 @@ function validAdblockRule(ruleText, allowedIP) {
     }
 
     // Check if the pattern does not start with the domain prefix and does not contain a domain separator
-    if (!_.startsWith(props.pattern, DOMAIN_PREFIX) || sepIdx === -1) {
+    if (!props.pattern.startsWith(DOMAIN_PREFIX) || sepIdx === -1) {
         return true;
     }
 
@@ -233,7 +230,7 @@ function validAdblockRule(ruleText, allowedIP) {
  * @returns {boolean} - true if the rule is valid, false otherwise
  */
 function valid(ruleText, allowedIP) {
-    if (ruleUtils.isComment(ruleText) || _.isEmpty(_.trim(ruleText))) {
+    if (ruleUtils.isComment(ruleText) || ruleText.trim().length === 0) {
         return true;
     }
 
@@ -280,7 +277,7 @@ class Validator {
         // preceding comments/empty lines if needed
         for (let i = filtered.length - 1; i >= 0; i -= 1) {
             const isValidRule = valid(filtered[i], this.allowedIP);
-            const isCommentOrEmptyLine = ruleUtils.isComment(filtered[i]) || _.isEmpty(filtered[i]);
+            const isCommentOrEmptyLine = ruleUtils.isComment(filtered[i]) || filtered[i].length === 0;
 
             if (!isValidRule) {
                 // If the rule is invalid, remove it and set the flag to remove preceding lines

src/utils.js

@@ -1,4 +1,4 @@
-const _ = require('lodash');
+const { escapeRegexp } = require('fast-escape-regexp');
 
 /**
  * Extracts a substring between two tags.
@@ -106,7 +106,7 @@ class Wildcard {
         } else if (str.includes('*')) {
             // Creates a RegExp from the given string, converting asterisks to .* expressions,
             // and escaping all other characters.
-            this.regex = new RegExp(`^${str.split(/\*+/).map(_.escapeRegExp).join('[\\s\\S]*')}$`, 'i');
+            this.regex = new RegExp(`^${str.split(/\*+/).map(escapeRegexp).join('[\\s\\S]*')}$`, 'i');
         }
     }
 

test/transformations/trim-lines.test.js

@@ -1,4 +1,3 @@
-const _ = require('lodash');
 const trimLines = require('../../src/transformations/trim-lines');
 
 describe('Trim lines', () => {
@@ -52,7 +51,7 @@ describe('Trim lines', () => {
     });
     it('test with three rules and comments', () => {
         const rules = [
-            _.repeat(' ', _.random(1, 10)), // ' ', '  ', ..., '      ' etc.
+            ' '.repeat(Math.floor(Math.random() * 10) + 1), // ' ', '  ', ..., '      ' etc.
             '    ! comment multiple   words    , ',
             '',
         ];