Compare Code Online: JS Diff Tool

Compare Code: Function vs Arrow

The sample loads a classic refactor: a function declaration rewritten as an arrow function. The diff shows exactly which tokens moved so reviewers confirm nothing else changed.

// original
function add(a, b) {
  return a + b;
}

// modified
const add = (a, b) => a + b;

Reading the Result

Removed tokens highlight on the left (function keyword, braces, return statement) and added tokens on the right (const, equals, arrow). Unchanged identifiers a and b stay neutral. If a rename slipped in, it would appear as a removed plus added pair on the same line.

Why This Refactor Matters

Arrow form is shorter and lexically binds this, which suits callbacks and module scope utilities. Function declarations hoist, so they can be called before their definition line. The diff proves the logic line a + b survived untouched while only the wrapper changed.

How to Use

1. The tool opens with both versions prefilled in side by side view
2. Edit either pane to diff your own snippets
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