rus-diff

library1.1.0jsnpmunverified

A MongoDB-compatible JSON diff library that computes differences between two JSON objects and produces delta objects using MongoDB operators like $set, $unset, $rename, and $inc. Version 1.1.0 currently stable; low release cadence (last update 2015). Key differentiators: output directly usable with MongoDB collection.update(), supports incremental diffs via $inc option, and provides apply() to apply diffs without manual traversal. Suitable for syncing JSON documents or generating MongoDB update commands.

database devops

npm install rus-diff

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INSTALL

IMPORT

SIG · RUS-DIFF

rus-diff

databasejavascriptv1.1.0

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

diff

✓ import { diff } from 'rus-diff'

✗ const diff = require('rus-diff').diff

ESM import works since package is dual. CommonJS require also works.

apply

✓ import { apply } from 'rus-diff'

Named import for applying diff to an object.

clone

✓ import { clone } from 'rus-diff'

✗ import clone from 'rus-diff'

clone is a named export, not default.

resolve

✓ import { resolve } from 'rus-diff'

✗ const resolve = require('rus-diff').resolve

resolve is a named export, not a default function.

Shows diffing two objects and applying the delta with clone to avoid mutation.

import { diff, apply, clone } from 'rus-diff'; const a = { a: 1, b: 'x', c: { d: 2 } }; const b = { a: 2, b: 'x', c: { d: 2 }, e: 3 }; const delta = diff(a, b); console.log(delta); // { $set: { a: 2, e: 3 }, $unset: { b: true } } // Apply delta (mutates a unless cloned) const copy = clone(a); apply(copy, delta); console.log(copy); // { a: 2, b: 'x', c: { d: 2 }, e: 3 }

Debug

Known issues

gotchaapply() mutates the target object in place. Always use clone(a) first if you want to preserve the original.

fix

Use apply(clone(a), delta) to avoid mutation.

affects: >=0.0.0

deprecatedOptions.inc (boolean) is deprecated and may be removed in future versions. Use explicit $inc handling instead.

fix

Manually compute numeric differences or use diff with { inc: true } but be aware it is not recommended for production.

affects: >=1.0.0

gotchaThe diff function does not detect array element moves; it treats arrays as atomic values. Use with caution for array-heavy documents.

fix

For arrays, consider manual comparison or a specialized diff library.

affects: >=0.0.0

breakingIn version 1.1.0, the default export was removed. Import named exports only.

fix

Use named imports like import { diff } from 'rus-diff' instead of default import.

affects: >=1.1.0

Errors

Common errors & fixes

TypeError: rus_diff_1.default is not a function

Using default import (import rusDiff from 'rus-diff') but package does not have default export in v1.1.0.

fix

Use named import: import { diff } from 'rus-diff'

Cannot find module 'babel/polyfill'

Old documentation suggests require('babel/polyfill') which is not needed in modern environments.

fix

Remove the require('babel/polyfill') line and use native ES6 features or add @babel/polyfill as a separate dependency.

Delta contains $inc but was not set in options

Passing { inc: true } to diff() is required to generate $inc operations for numeric changes.

fix

Call diff(a, b, [], { inc: true }) to enable $inc.

Invalid update: $rename: { ... } is not allowed with other operators in same object

MongoDB does not allow $rename combined with $set, $unset in the same update object.

fix

Apply $rename separately or use apply() which handles it correctly.

Upgrade

Version history

1.1.0latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

13 hits · last 30 days

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