@goodnight-dev/predicate

Runtime type and value predicates (is*) — part of the @goodnight-dev utility suite. Not limited to one input type: a predicate's name and signature say what it checks (isAsciiString, and more to come).

Strict, modern, ESM-only TypeScript. Fully typed, tree-shakable, zero runtime dependencies.

Install

# via pnpm
pnpm add @goodnight-dev/predicate
# or via npm
npm install @goodnight-dev/predicate
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Usage

import { isAsciiString } from '@goodnight-dev/predicate';

isAsciiString('hello'); // => true
isAsciiString('café'); // => false
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The same utilities are available through the umbrella package, if you'd rather depend on one thing:

import { isAsciiString } from '@goodnight-dev/utils/predicate';
import { isAsciiString } from '@goodnight-dev/utils';
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API

isAsciiString(value: string): boolean

Returns true if every character in the string is ASCII (U+0000–U+007F), false otherwise (and true for an empty string). See the implementation notes for the alternatives considered and why this approach was chosen.

isIterable(value: unknown): boolean

Returns true if the value implements the iterable protocol (a callable Symbol.iterator), so it can drive a for...of loop or the spread operator — true for arrays, strings, Map, Set, and generator objects; false for plain objects, null, and undefined. See the implementation notes for the alternatives considered and why this approach was chosen.

License

MIT © Ian Goodnight