README.md

deep-diff-ts — Fast Deep Object Diff for TypeScript

Fast deep object diff and patch with full TypeScript types. Compare nested objects, arrays, dates, and regexps. Zero dependencies, ~1.4KB.

Install

npm install deep-diff-ts

Usage

import { diff } from "deep-diff-ts";

const oldObj = {
  name: "Alice",
  age: 30,
  tags: ["admin"],
  config: { theme: "dark" },
};

const newObj = {
  name: "Alice",
  age: 31,
  tags: ["admin", "editor"],
  config: { theme: "light" },
};

const changes = diff(oldObj, newObj);
// [
//   { type: "UPDATE", path: ["age"], oldValue: 30, value: 31 },
//   { type: "CREATE", path: ["tags", 1], value: "editor" },
//   { type: "UPDATE", path: ["config", "theme"], oldValue: "dark", value: "light" }
// ]

Apply Diffs

import { diff, applyDiff } from "deep-diff-ts";

const changes = diff(oldObj, newObj);
const result = applyDiff(oldObj, changes);
// result deeply equals newObj
// oldObj is not mutated

Diff Types

Each difference has a type and path:

Type	Fields	Description
CREATE	path, value	Property was added
UPDATE	path, oldValue, value	Property value changed
DELETE	path, oldValue	Property was removed

path is an array of keys/indices: ["users", 0, "name"]

Supported Types

• Objects (deep recursive)
• Arrays (element-by-element)
• Dates (compared by time value)
• RegExps (compared by string representation)
• Primitives (string, number, boolean, null, undefined)
• NaN (correctly handled via Object.is)

API

diff(oldObj, newObj)

Returns Difference[] describing all changes from oldObj to newObj.

applyDiff(target, diffs)

Returns a new object with all diffs applied. Does not mutate the original.

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Author

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License

MIT