How to use map function in vue

The Vue.js map function is a built-in higher-order function that creates a new array where each element is the transformed result of each element in the original array. The syntax is map(callbackFn), where callbackFn receives each element in the array as the first argument, optionally the index as the second argument, and returns a value. The map function does not change the original array.

The map function in Vue.js

The map function is a built-in higher-order function in Vue.js , used to create a new array in which each element is the result of a transformation based on each element in the original array.

Syntax:

<code class="javascript">map(callbackFn)</code>

Parameters:

• callbackFn: A function that receives Each element in the array is received as the first argument, optionally receiving the index as the second argument.

Return value:

A new array in which each element is the conversion result of the corresponding element in the original array.

Usage:

The map function can be used with array methods as follows:

<code class="javascript">const numbers = [1, 2, 3, 4, 5];

// 将每个元素乘以 2
const doubledNumbers = numbers.map(number => number * 2);

// 输出：[2, 4, 6, 8, 10]
console.log(doubledNumbers);</code>

Example:

The map function can be used to:

• Convert the element type in the array
• Create a new array that only contains elements in the original array that meet certain conditions
• Extract specific properties or values ​​of nested objects or arrays in an array

Example usage:

<code class="javascript">// 创建一个新数组，只包含名字为 "John" 的用户
const users = [{ name: "John", age: 30 }, { name: "Jane", age: 25 }];
const johnUsers = users.map(user => user.name === "John" ? user : null);

// 提取每个产品的价格
const products = [{ name: "Product 1", price: 10 }, { name: "Product 2", price: 15 }];
const prices = products.map(product => product.price);</code>

Notes:

• The map function does not change the original array.
• callbackFn must return a value. If no value is returned, the corresponding element in the new array will be undefined.

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