Squash Object

mediumcodingJavaScriptObjectsRecursion~25 min

Asked at Google, Meta, Amazon

Overview

Implement squashObject(object) that flattens nested object keys using dot notation.

Examples

squashObject({ a: { b: 1, c: { d: 2 }}}); // { 'a.b': 1, 'a.c.d': 2 }

Solution

Reveal solution

function squashObject(object) {
  const result = {};
  function recurse(obj, prefix) {
    for (const [k, v] of Object.entries(obj)) {
      const key = prefix ? `${prefix}.${k}` : k;
      if (v !== null && typeof v === 'object' && !Array.isArray(v)) {
        recurse(v, key);
      } else {
        result[key] = v;
      }
    }
  }
  recurse(object, '');
  return result;
}

squash-object.js

Squash Object

mediumcodingJavaScriptObjects

Overview

Implement squashObject(object) that flattens nested object keys using dot notation.

Examples

squashObject({ a: { b: 1, c: { d: 2 }}}); // { 'a.b': 1, 'a.c.d': 2 }

Solution

Reveal solution

function squashObject(object) {
  const result = {};
  function recurse(obj, prefix) {
    for (const [k, v] of Object.entries(obj)) {
      const key = prefix ? `${prefix}.${k}` : k;
      if (v !== null && typeof v === 'object' && !Array.isArray(v)) {
        recurse(v, key);
      } else {
        result[key] = v;
      }
    }
  }
  recurse(object, '');
  return result;
}

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