lpm install @lpm.dev/neo.diff

import { diffLines, diffWords, diffChars } from "@lpm.dev/neo.diff";

// Line-by-line diff (most common)
const lineDiff = diffLines(
  "line 1\nline 2\nline 3",
  "line 1\nmodified\nline 3",
);
// => [
//   { value: 'line 1\n', count: 1 },
//   { value: 'line 2', removed: true, count: 1 },
//   { value: 'modified', added: true, count: 1 },
//   { value: '\nline 3', count: 1 }
// ]

// Word-by-word diff
const wordDiff = diffWords("Hello world", "Hello there");

// Character-by-character diff
const charDiff = diffChars("abc", "adc");

import { diffLinesPatiently } from "@lpm.dev/neo.diff";

// Produces more readable diffs for code with moved blocks
const diff = diffLinesPatiently(oldCode, newCode);

import { diffJson, diffArrays, diffObjects } from "@lpm.dev/neo.diff";

// JSON diff (stringifies and diffs line-by-line)
const jsonDiff = diffJson({ name: "John", age: 30 }, { name: "John", age: 31 });

// Array diff
const arrayDiff = diffArrays([1, 2, 3], [1, 2, 4]);

// Object diff (microdiff-style with CREATE/REMOVE/CHANGE)
const objectDiff = diffObjects({ a: 1, b: 2 }, { a: 1, b: 20, c: 3 });
// => [
//   { type: 'CHANGE', path: ['b'], oldValue: 2, value: 20 },
//   { type: 'CREATE', path: ['c'], value: 3 }
// ]

import { createPatch, formatPatch, applyPatch } from "@lpm.dev/neo.diff";

const old = "line 1\nline 2\nline 3";
const newText = "line 1\nmodified\nline 3";

// Create patch
const patch = createPatch(old, newText, "file.txt", "file.txt");

// Format as unified diff
const formatted = formatPatch(patch);
// --- file.txt
// +++ file.txt
// @@ -1,3 +1,3 @@
//  line 1
// -line 2
// +modified
//  line 3

// Apply patch
const result = applyPatch(old, formatted);
// => 'line 1\nmodified\nline 3'

diffLines("line 1\nline 2", "line 1\nline 3");

diffJson({ name: "John" }, { name: "Jane" });

diffArrays([1, 2, 3], [1, 2, 4]);

// With custom equality
diffArrays(users, newUsers, (a, b) => a.id === b.id);

diffObjects({ a: 1 }, { a: 2, b: 3 });
// => [
//   { type: 'CHANGE', path: ['a'], oldValue: 1, value: 2 },
//   { type: 'CREATE', path: ['b'], value: 3 }
// ]

const changes = diffObjects(oldObj, newObj);
const result = applyChanges(oldObj, changes);
// result === newObj

applyPatch(source, patchString, { fuzzFactor: 2 });

// Full bundle (~12 KB)
import * as diff from "@lpm.dev/neo.diff";

// Single function (~50-200 bytes)
import { diffLines } from "@lpm.dev/neo.diff";

// Category import
import { diffLines, diffWords } from "@lpm.dev/neo.diff/text";
import { diffJson, diffObjects } from "@lpm.dev/neo.diff/structured";

interface DiffOptions {
  context?: number; // Number of context lines (default: 3)
  ignoreWhitespace?: boolean; // Ignore whitespace (default: false)
  ignoreCase?: boolean; // Ignore case (default: false)
  algorithm?: "myers" | "patience" | "histogram" | "lcs";
}

interface PatchOptions {
  context?: number; // Context lines (default: 3)
  newlineAtEnd?: boolean; // Add newline at end (default: true)
  ignoreWhitespace?: boolean; // Ignore whitespace (default: false)
}

import { createTwoFilesPatch } from "@lpm.dev/neo.diff";

const patch = createTwoFilesPatch(
  oldContent,
  newContent,
  "a/src/file.ts",
  "b/src/file.ts",
  "Original",
  "Modified",
);

console.log(patch);
// --- a/src/file.ts  Original
// +++ b/src/file.ts  Modified
// @@ -1,5 +1,5 @@
// ...

import { diffLines } from "@lpm.dev/neo.diff";

function assertTextEquals(expected: string, actual: string) {
  if (expected === actual) return;

  const diff = diffLines(expected, actual);
  const message = diff
    .map((change) => {
      if (change.added) return `+ ${change.value}`;
      if (change.removed) return `- ${change.value}`;
      return `  ${change.value}`;
    })
    .join("\n");

  throw new Error(`Text mismatch:\n${message}`);
}

import { diffObjects } from "@lpm.dev/neo.diff";

const expected = { status: 200, data: { id: 1, name: "Test" } };
const actual = { status: 200, data: { id: 1, name: "Production" } };

const changes = diffObjects(expected, actual);
// => [{ type: 'CHANGE', path: ['data', 'name'], oldValue: 'Test', value: 'Production' }]

import { diffJson } from "@lpm.dev/neo.diff";

const oldConfig = { port: 3000, host: "localhost" };
const newConfig = { port: 8080, host: "localhost", ssl: true };

const diff = diffJson(oldConfig, newConfig);
// See exactly what changed in config

import type {
  DiffResult,
  DiffChange,
  StructuredDiffChange,
} from "@lpm.dev/neo.diff";

const changes: DiffResult = diffLines(old, newText);
const change: DiffChange = changes[0];

if (change.added) {
  console.log("Added:", change.value);
}