no-useless-escapes has false positives for periods and meta sequences.

Tell us about your environment

• ESLint Version: 4.10.0
• Node Version: 9.0.0
• npm Version: 5.5.1

What parser (default, Babel-ESLint, etc.) are you using? default Please show your full configuration:

Configuration

{
	"env": {
		"es6": true,
		"node": true
	},
	"extends": "eslint:recommended",
	"rules": {
		"indent": [2, "tab"],
		"linebreak-style": [2, "unix"],
		"quotes": [2, "double"],
		"semi": [2, "always"]
	},
	"parserOptions": {
		"sourceType": "module",
		"ecmaVersion": 2017
	}
}

What did you do? Please include the actual source code causing the issue, as well as the command that you used to run ESLint.

this.regexes = {
	suffix: new RegExp("^(\d+(\.\d*)?|\.\d+)(e[+-]?\d+)?(" + this.suffixes.join("|") + ")?$", "i"),
	suffix_strict: new RegExp("^(\d+(\.\d*)?|\.\d+)(e[+-]?\d+)?(" + this.suffixes.join("|") + ")$", "i")
};

eslint src/**

What did you expect to happen? It wouldn’t complain about correct regex. What actually happened? Please include the actual, raw output from ESLint. It claimed the escapes were useless when they were needed.

[LJNeon]

   9:26  error  Unnecessary escape character: \d  no-useless-escape
   9:30  error  Unnecessary escape character: \.  no-useless-escape
   9:32  error  Unnecessary escape character: \d  no-useless-escape
   9:38  error  Unnecessary escape character: \.  no-useless-escape
   9:40  error  Unnecessary escape character: \d  no-useless-escape
   9:51  error  Unnecessary escape character: \d  no-useless-escape
  10:33  error  Unnecessary escape character: \d  no-useless-escape
  10:37  error  Unnecessary escape character: \.  no-useless-escape
  10:39  error  Unnecessary escape character: \d  no-useless-escape
  10:45  error  Unnecessary escape character: \.  no-useless-escape
  10:47  error  Unnecessary escape character: \d  no-useless-escape
  10:58  error  Unnecessary escape character: \d  no-useless-escape

here’s the actual eslint output lmao, mixed up the two issues I opened.

[LJNeon]

and yeah that was the problem, thanks for clarifying.