p-lazy

Create a lazy promise that defers execution until it's awaited or when .then() or .catch() is called

Useful if you're doing some heavy operations and would like to only do it when the promise is actually used.

Install

$ npm install p-lazy

Usage

const PLazy = require('p-lazy');

const lazyPromise = new PLazy(resolve => {
	someHeavyOperation(resolve);
});

// `someHeavyOperation` is not yet called

(async () => {
	await doSomethingFun;
	// `someHeavyOperation` is called
	console.log(await lazyPromise);
})();

API

new PLazy(executor)

Same as the Promise constructor. PLazy is a subclass of Promise.

PLazy.from(fn)

Create a PLazy promise from a promise-returning or async function.

PLazy.resolve(value)

Create a PLazy promise that is resolved with the given value, or the promise passed as value.

PLazy.reject(reason)

Create a PLazy promise that is rejected with the given reason.

Related

• p-cancelable - Create a promise that can be canceled
• p-defer - Create a deferred promise
• lazy-value - Create a lazily evaluated value
• define-lazy-prop - Define a lazily evaluated property on an object
• More…

License

MIT © Sindre Sorhus