The has()
method of Map
instances returns a boolean indicating whether an element with the specified key exists in this map or not.
The has()
method of Map
instances returns a boolean indicating whether an element with the specified key exists in this map or not.
has(key)
key
The key of the element to test for presence in the Map
object.
true
if an element with the specified key exists in the Map
object; otherwise false
.
const myMap = new Map(); myMap.set("bar", "foo"); console.log(myMap.has("bar")); // true console.log(myMap.has("baz")); // false
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Chrome | Edge | Firefox | Opera | Safari | Chrome Android | Firefox for Android | Opera Android | Safari on IOS | Samsung Internet | WebView Android | Deno | Node.js | ||
has |
38 | 12 | 13 | 25 | 8 | 38 | 14 | 25 | 8 | 3.0 | 38 | 1.0 | 0.12.0 |
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https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/has