- Data Structure
- Networking
- RDBMS
- Operating System
- Java
- MS Excel
- iOS
- HTML
- CSS
- Android
- Python
- C Programming
- C++
- C#
- MongoDB
- MySQL
- Javascript
- PHP
- Physics
- Chemistry
- Biology
- Mathematics
- English
- Economics
- Psychology
- Social Studies
- Fashion Studies
- Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
Fetching JavaScript keys by their values - JavaScript
Suppose, we have an object like this −
const products = { "Pineapple":38, "Apple":110, "Pear":109 };
All the keys are unique in themselves and all the values are unique in themselves. We are required to write a function that accepts a value and returns its key
For example: findKey(110) should return −
"Apple"
We will approach this problem by first reverse mapping the values to keys and then simply using object notations to find their values.
Example
Following is the code −
const products = { "Pineapple":38, "Apple":110, "Pear":109 }; const findKey = (obj, val) => { const res = {}; Object.keys(obj).map(key => { res[obj[key]] = key; }); // if the value is not present in the object // return false return res[val] || false; }; console.log(findKey(products, 110));
Output
This will produce the following output in console −
Apple
Advertisements