JS : .findIndex() Method

admin

We sometimes want to find the location of an element in an array. That’s where the .findIndex() method comes in! Calling .findIndex() on an array will return the index of the first element that evaluates to true in the callback function.

1. const animals = ['hippo', 'tiger', 'lion', 'seal', 'cheetah', 'monkey', 'salamander', 'elephant'];
   
2. 
   
3. const foundAnimal = animals.findIndex(animal => {
   
4.   return animal === 'elephant';
   
5. });
   
6. 
   
7. const startsWithS = animals.findIndex(animal => {
   
8.   return animal[0] === 's';
   
9. });

複製代碼

return 的是 index 的數字。