Converts value to an integer suitable as the length of an array-like object. Runs _.toInteger, then clamps to [0, 232−1] (4294967295). Part of Lodash 4.x Lang (since 4.0.0).
Pass the value you want to inspect or convert. Read the return type carefully before you use the result.
Call _.toLength. Start with this line.
_.toLength(value)| Call | What it does |
|---|---|
_.toLength(value) | Primary signature. |
Prefer import toLength from "lodash/toLength" when you want a smaller bundle.
_.toLength(value)| Parameter | Description |
|---|---|
| value | Required. Any value to convert |
| Return Value | Description |
|---|---|
| * | Integer in [0, 2^32−1] |
Decimals become whole lengths; strings parse first.
_.toLength(3.2);
// → 3
_.toLength("3.2");
// → 33.2 truncates toward zero → 3.3 is already inside [0, max]."3.2" parses the same way.Number.MIN_VALUE → 0Tiny positives disappear after integer conversion.
_.toLength(Number.MIN_VALUE);
// → 0
_.toInteger(Number.MIN_VALUE);
// → 0MIN_VALUE is about 5e-324.0.0 is already the lower bound.Infinity → 4294967295Huge values stop at the max legal array length.
_.toLength(Infinity);
// → 4294967295
_.toInteger(Infinity);
// → 1.7976931348623157e+308Infinity to Number.MAX_VALUE.2^32−1.The clamp is what makes toLength different from toInteger.
_.toLength(-5);
// → 0
_.toInteger(-5);
// → -5
_.toLength(4294967296);
// → 4294967295
_.toLength(-Infinity);
// → 00.4294967295.-5 — no length clamp.new Array(n)Sanitize untrusted sizes before allocating.
function makeBuffer(requested) {
var size = _.toLength(requested);
return new Array(size);
}
makeBuffer(3.9).length;
// → 3
makeBuffer(-1).length;
// → 0
makeBuffer(9e99).length;
// → 4294967295toLength guarantees a legal length.new Array(size) will not throw “Invalid array length.”3.9 becomes length 3._.toLength is a Lodash 4.x Lang helper (since 4.0.0). It runs anywhere Lodash runs — modern browsers (CDN or bundle) and Node.js / Bun / Deno with npm install lodash. It mirrors ECMAScript ToLength; there is no single built-in of the same name, so Lodash (or a manual clamp) is the practical API.
Available in [email protected] full builds and the lodash/toLength modular import. Works in evergreen browsers and current Node LTS when Lodash is installed.
Bottom line: Safe for production once Lodash is loaded. Prefer import toLength from "lodash/toLength" for smaller builds. Ideal before new Array(n), indexed loops, and untrusted size inputs.
Convert a value to a number — the raw coercion behind these helpers.
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