Creates a new pristine Lodash function using an optional context object. The copy is independent of the shared _ — mixins on one do not appear on the other. Part of Lodash Util (stable — not deprecated).
Pass the arguments shown below. Prefer modular imports when you only need this helper.
Call _.runInContext. Start with this line.
_.runInContext([context=root])| Call | What it does |
|---|---|
_.runInContext([context=root]) | Primary signature. |
_.runInContext(...) | Call the util helper. |
Prefer import runInContext from "lodash/runInContext" when you want a smaller bundle.
_.runInContext([context=root])| Parameter | Description |
|---|---|
| context | Optional. Object supplying natives (default: root / global) |
| Return Value | Description |
|---|---|
| * | A new Lodash function |
Mixins on the copy stay off the shared _.
var lodash = _.runInContext();
lodash.mixin({ 'bar': lodash.constant('bar') });
_.isFunction(_.bar);
// → false
lodash.isFunction(lodash.bar);
// → truerunInContext() returns a pristine Lodash.bar is added only to that copy._.bar is missing → false.lodash.bar exists → true.Ship helpers on an isolated Lodash so apps stay clean.
var lodash = _.runInContext();
lodash.mixin({
double: function (n) {
return n * 2;
}
});
lodash.double(21);
// → 42
typeof _.double;
// → 'undefined'double lives only there.lodash.double(21) → 42._ has no double.Override natives Lodash uses — Node example from the docs.
// Official Node.js idea: use setImmediate instead of setTimeout
// var defer = _.runInContext({ 'setTimeout': setImmediate }).defer;
// Browser-friendly mock of the same idea:
var ticks = 0;
var lodash = _.runInContext({
setTimeout: function (fn) {
ticks += 1;
fn();
}
});
lodash.defer(function () {});
// ticks → 1 (mock ran immediately)setImmediate as setTimeout.setTimeout runs the callback and counts ticks.runInContext vs noConflictDifferent goals: clone Lodash vs free the _ name.
// runInContext — extra Lodash; global _ unchanged
var lodash = _.runInContext();
typeof _.map;
// → 'function'
lodash === _;
// → false
// noConflict — restore previous global _; keep one Lodash handle
// var lodash = _.noConflict();
// // window._ is no longer this Lodash_ stays put._._.runInContext is a Lodash Util helper (stable). It needs the full Lodash build — modular single-method imports do not include it. Works in modern browsers (CDN) and Node.js / Bun / Deno with npm install lodash.
Available in [email protected] full builds. Custom context overrides (e.g. setImmediate) are most useful in Node. Evergreen browsers and current Node LTS are fine when Lodash is loaded.
Bottom line: Use the full lodash package or CDN build. Create one isolated copy for plugins; mixin on that copy, not the shared _.
Return a brand-new empty array on every call.
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