Returns true if the key is defined in the provided collection.

has(collection: object, key: unknown): boolean


A functional alternative to collection.has(key) which will also work with plain Objects and Arrays as an alternative for collection.hasOwnProperty(key).

const { has } = require('immutable') has([ 'dog', 'frog', 'cat' ], 2) // true has([ 'dog', 'frog', 'cat' ], 5) // false has({ x: 123, y: 456 }, 'x') // true has({ x: 123, y: 456 }, 'z') // falserun it
This documentation is generated from immutable.d.ts. Pull requests and Issues welcome.