no-inferrable-types
Last updated: 2025-01-23
Disallows easily inferrable types.
Variable initializations to JavaScript primitives (and null) are obvious in
their type. Specifying their type can add additional verbosity to the code. For
example, with const x: number = 5, specifying number is unnecessary as it is
obvious that 5 is a number.
Invalid:
const a: bigint = 10n;
const b: bigint = BigInt(10);
const c: boolean = true;
const d: boolean = !0;
const e: number = 10;
const f: number = Number("1");
const g: number = Infinity;
const h: number = NaN;
const i: null = null;
const j: RegExp = /a/;
const k: RegExp = RegExp("a");
const l: RegExp = new RegExp("a");
const m: string = "str";
const n: string = `str`;
const o: string = String(1);
const p: symbol = Symbol("a");
const q: undefined = undefined;
const r: undefined = void someValue;
class Foo {
prop: number = 5;
}
function fn(s: number = 5, t: boolean = true) {}
Valid:
const a = 10n;
const b = BigInt(10);
const c = true;
const d = !0;
const e = 10;
const f = Number("1");
const g = Infinity;
const h = NaN;
const i = null;
const j = /a/;
const k = RegExp("a");
const l = new RegExp("a");
const m = "str";
const n = `str`;
const o = String(1);
const p = Symbol("a");
const q = undefined;
const r = void someValue;
class Foo {
prop = 5;
}
function fn(s = 5, t = true) {}