Value equality check with semantics similar to Object.is, but treats
Immutable Collections as values, equal if the second Collection includes
equivalent values.
is(first: unknown, second: unknown): boolean
It's used throughout Immutable when checking for equality, including Map
key equality and Set membership.
const { Map, is } = require('immutable')
const map1 = Map({ a: 1, b: 1, c: 1 })
const map2 = Map({ a: 1, b: 1, c: 1 })
assert.equal(map1 !== map2, true)
assert.equal(Object.is(map1, map2), false)
assert.equal(is(map1, map2), true)run itis() compares primitive types like strings and numbers, Immutable.js
collections like Map and List, but also any custom object which
implements ValueObject by providing equals() and hashCode() methods.
Note: Unlike Object.is, Immutable.is assumes 0 and -0 are the same
value, matching the behavior of ES6 Map key equality.