javascript - React Native - How to pass index in map function - Stack Overflow

admin管理员组

文章数量:1208155

I have a map function to create a component repetitively and dynamically. Suppose it's like this:

renderBoxes() {
    return Array.map(data => this.myFunction(indexOfThisArray));
} 

How can I pass the index of the array? So that the 'myFunction' function gets the index value everytime it is called.

I have a map function to create a component repetitively and dynamically. Suppose it's like this:

renderBoxes() {
    return Array.map(data => this.myFunction(indexOfThisArray));
} 

How can I pass the index of the array? So that the 'myFunction' function gets the index value everytime it is called.

• javascript
• arrays
• reactjs
• react-native
• react-router

Share Improve this question Follow edited Sep 4, 2017 at 18:20 imjared 20.6k44 gold badges5555 silver badges7575 bronze badges asked Sep 4, 2017 at 18:13 prasang7prasang7 57122 gold badges1111 silver badges3131 bronze badges 1

• 1 at least you saved my some time lol – Bikram Thapa Commented Feb 18, 2019 at 6:22

Add a comment  | 

3 Answers 3

Sorted by: Reset to default 15

Map provides second argument as the index of the current element and third argument as the whole array itself.

renderBoxes() {
    return Array.map((data, index, array) => this.myFunction(index));
} 

Read more about Array.prototype.map

the syntax of map is

var new_array = arr.map(function callback(currentValue, index, array) {
    // Return element for new_array
}[, thisArg])

source. You can find the index as the 2nd parameter in the callback function

Simply pass a second arguments to your arrow function (data, index)

renderBoxes() {
    return Array.map((data, index) => this.myFunction(indexOfThisArray));
} 

Signaure for .map

var new_array = arr.map(function callback(currentValue, index, array) {
    // Return element for new_array
}[, thisArg])

本文标签： javascriptReact NativeHow to pass index in map functionStack Overflow