learn how to cleanly rename object property names in javascript—ideal for api response transformation in low-code platforms like budibase.

learn how to cleanly rename object property names in javascript—ideal for api response transformation in low-code platforms like budibase.

When working with third-party API responses, the field names often don’t match your frontend or UI framework’s expectations (e.g., Budibase expects name and value for dropdown or chart components). Renaming keys is a common but critical data-mapping task—and doing it incorrectly (like trying to Object.assign onto a string key name) leads to silent failures, as seen in the original attempt.

The core issue in the provided code is a fundamental misunderstanding of how for...in loops and Object.assign work:

• for (let dict in dicts) iterates over property names ("sales", "city"), not values — so dict is a string, not an object.
• Object.assign(dictionary, {...}) fails because dictionary is a string (immutable), not an object reference.
• There's no actual object being transformed — just malformed mutations on primitives.

✅ Here's the correct, simple, and safe approach:

const apiResponse = {
  "sales": 312,
  "city": "Berlin"
};

const renamed = {
  value: apiResponse.sales,
  name: apiResponse.city
};

console.log(renamed); 
// → { value: 312, name: "Berlin" }

For dynamic or reusable renaming (especially useful in Budibase JS transforms), use a mapping configuration:

Java Maven Code Review

审查Java Maven项目（ZIP压缩包或GitLab仓库URL），检查代码规范、命名、模块边界、可维护性问题以及重复代码。

下载

立即学习“Java免费学习笔记（深入）”；

function renameKeys(obj, keyMap) {
  return Object.keys(keyMap).reduce((acc, oldKey) => {
    const newKey = keyMap[oldKey];
    if (obj.hasOwnProperty(oldKey)) {
      acc[newKey] = obj[oldKey];
    }
    return acc;
  }, {});
}

// Usage:
const result = renameKeys(apiResponse, {
  sales: 'value',
  city: 'name'
});
// → { value: 312, name: "Berlin" }

? Pro Tips for Budibase Users:

• Avoid mutating the original object — always return a new object (Budibase’s JS transforms expect pure functions).
• Handle missing keys gracefully (e.g., add fallbacks like obj[oldKey] ?? null).
• If your API returns an array of such objects, wrap the rename logic in .map():

  data.map(item => renameKeys(item, { sales: 'value', city: 'name' }))

❌ Never do this:

// ❌ Wrong: assigning to strings, deleting from iteration variables  
for (let key in obj) { delete key['sales']; } // key is a string — deletion does nothing

In summary: rename keys by explicitly constructing a new object (or using reduce + a map), not by misusing Object.assign or for...in. Keep it functional, readable, and safe — especially in low-code environments where debugging is limited.