daily-utils

Tiny daily TypeScript utilities.

Install

npm i daily-utils

Usage

JavaScript (CommonJS)

const { isDefined } = require("daily-utils");

const values = [1, null, 2, undefined, 3];
const definedOnly = values.filter(isDefined); // [1, 2, 3]

TypeScript

import { isDefined } from "daily-utils";

const values: Array<number | null | undefined> = [1, null, 2, undefined, 3];
const definedOnly = values.filter(isDefined); // number[]

API

isDefined(value)

Type guard that checks whether a value is neither null nor undefined.

export function isDefined<T>(value: T | null | undefined): value is T;

Examples

Filter out null / undefined:

import { isDefined } from "daily-utils";

const xs = ["a", null, "b", undefined].filter(isDefined);
// xs: string[]

Narrow inside conditionals:

import { isDefined } from "daily-utils";

const maybeId: string | null | undefined = process.env.USER_ID;

if (isDefined(maybeId)) {
  // maybeId: string
  console.log(maybeId.toUpperCase());
}

Development

npm run build

License

ISC