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A tool for merging objects.
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fmerge is a simple tool for merging objects. It is perfect for handling options objects.

It takes any number of parameters. It even merges recursively. Arrays will just be replaced, though.

It does require a browser that supports ES5 methods though, so for IE8 or earlier, take a look at


Installing is easy. It automatically detects the environment among the three supported types (node.js, require.js and normal browser version).

  • In node, simply use npm install fmerge.
  • The module is require.js-aware, so you can link it directly through require.js as well.
    • To make the require.js version, either install through npm or check out from git and run node install.js.
  • For normal browsers, it creates a global function fmerge.

Example of use

var merge = require('fmerge')

  { a: 1, b: { c: 3, d: 4 }, c: [ 'entry', { e: 5 } ] }
, { a: 2, b: { a: 1, c: 2 }, c: [ 'another entry', { a: 1 } ] }
// { a: 2, b: { a: 1, c: 2, d: 4 }, c: [ 'another entry', { a: 1 } ] }

Circular ref detection

The default function have built-in circular ref detection, but this comes at a performance cost. If you think that you don't need this, then you can skip it by calling merge.skipCircularGuard() instead of merge().

var merge = require('fmerge')

// with circular detection
merge(first, second)

// without circular detection
merge.skipCircularGuard(first, second)
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