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Rslint

    init-declarations

    Configuration

    rslint.config.ts
    import { defineConfig, ts } from '@rslint/core';

export default defineConfig([
  ts.configs.recommended,
  {
    rules: {
      '@typescript-eslint/init-declarations': 'error',
    },
  },
]);

    Rule Details

    Require or disallow initialization in variable declarations. This is the TypeScript-aware version of the ESLint init-declarations rule: bindings introduced by declare (either on the declaration itself or on an enclosing declare namespace / declare module 'm' / declare global) are skipped.

    Examples of incorrect code for this rule:

    var foo;
var bar: string;
let baz;
namespace myLib {
  let count: number;
}

    Examples of correct code for this rule:

    var foo = null;
let bar: string = 'hi';
const baz = 0;
declare const x: number;
declare namespace myLib {
  let count: number;
}

    Options

    mode

    Type: "always" | "never" — Default: "always"

    When set to "always", every variable declaration must include an initializer. When set to "never", declarators that include an initializer are reported. const, using, and await using bindings are exempt from "never" because they require an initializer at parse time.

    Examples of incorrect code with "never":

    { "@typescript-eslint/init-declarations": ["error", "never"] }
    var foo = 1;
let bar: string = 'hi';
for (var i = 0; i < 1; i++) {}

    Examples of correct code with "never":

    { "@typescript-eslint/init-declarations": ["error", "never"] }
    var foo;
let bar: string;
const baz = 1;

    ignoreForLoopInit

    Type: boolean — Default: false

    Only meaningful when mode is "never". When true, declarators in the initializer / left slot of for, for-in, and for-of statements are not reported.

    Examples of correct code with ["never", { "ignoreForLoopInit": true }]:

    { "@typescript-eslint/init-declarations": ["error", "never", { "ignoreForLoopInit": true }] }
    for (var i = 0; i < 1; i++) {}
for (var key in obj) {
}
for (var item of items) {
}

    Original Documentation