Checks if value is classified as a Map object. Part of Lodash Lang since 4.3.0 (stable — not deprecated).
Pass the value you want to inspect or convert. Read the return type carefully before you use the result.
Call _.isMap. Start with this line.
_.isMap(value)| Call | What it does |
|---|---|
_.isMap(value) | Primary signature. |
Prefer import isMap from "lodash/isMap" when you want a smaller bundle.
_.isMap(value)| Parameter | Description |
|---|---|
| value | Required. The value to check |
| Return Value | Description |
|---|---|
| * | true if Map, else false |
new MapA real Map instance is classified as a Map.
_.isMap(new Map);
// → truenew Map (empty Map).[object Map].true — it is a Map.new WeakMapWeakMap is a different built-in — not a Map.
_.isMap(new WeakMap);
// → falsenew WeakMap.[object WeakMap].false._.isWeakMap for WeakMaps.Populated Maps still pass — size is irrelevant.
var m = new Map();
m.set("a", 1);
m.set("b", 2);
_.isMap(m);
// → true
_.isMap(new Map());
// → true_.isMap(m) looks at type, not .size.new Map() also returns true.Objects and Maps both store keys, but only Map instances pass.
_.isMap({ a: 1 }); // → false
_.isMap(Object.create(null)); // → false
_.isMap(new Map([["a", 1]])); // → true{ a: 1 } is not a Map.Object.create(null) also fails.new Map(...) → true._.isPlainObject for {}.Other collections and nullish values are not Maps.
_.isMap(new Set([1, 2])); // → false
_.isMap([1, 2]); // → false
_.isMap(null); // → false
_.isMap(undefined); // → false_.isSet.null / undefined fail cleanly._.isMap is a Lodash Lang helper (available since 4.3.0, stable in 4.x). It runs anywhere Lodash runs — modern browsers (via CDN or bundle) and Node.js / Bun / Deno with npm install lodash. The host must also provide the ES Map built-in (all evergreen engines do).
Available in [email protected] full builds and the lodash/isMap modular import. Works in evergreen browsers and current Node LTS when Lodash is installed.
Bottom line: Safe for production once Lodash is on the page or in your bundle. Prefer import isMap from "lodash/isMap" for smaller builds. Native alternative: value instanceof Map (note iframe/realm caveats).
Perform a partial deep comparison between an object and a source.
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