快来看看JS数组中常用的方法吧！ 原创

const arr = [];
const length = arr.push("pink", "cyan");
console.log(length) // 2
console.log('arr: ', arr); // [ 'pink', 'cyan' ]
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const arr = [ 'red' ];
const length = arr.unshift("pink", "cyan");
console.log(length) // 3
console.log('arr: ', arr); // [ 'pink', 'cyan', 'red' ]
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const arr = [ "pink", "cyan", 'red' ];
const emptyArr = arr.splice(1, 0, 'white', 'black'); // 从下标为 1 的元素开始，删除 0 个，添加 2 个
console.log(emptyArr) // [ ]
console.log('arr: ', arr); // [ 'pink', 'white', 'black', 'cyan', 'red' ]
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const arr1 = [ "pink", "cyan" ];
const arr2 = [ 'white', 'black' ];
const newArr = arr1.concat(arr2);
console.log('newArr: ', newArr); // [ 'pink', 'cyan', 'white', 'black' ]
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const newArr = [...arr1, ...arr2]
console.log('newArr: ', newArr); // [ 'pink', 'cyan', 'white', 'black' ]
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const arr = ["pink", "cyan"];
const deleteItem = arr.pop();
console.log(deleteItem) // cyan
console.log('arr: ', arr); // [ 'pink' ]
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const arr = ["pink", "cyan"];
const deleteItem = arr.shift();
console.log(deleteItem) // pink
console.log('arr: ', arr); // [ 'cyan' ]
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const colors1 = ["red", "green", "blue", "yellow", "purple"];
const colors2 = colors1.slice(1); // 从下标为 1 开始截取到最后一个
const colors3 = colors1.slice(1, 4); // 从下标为 1 开始到截取到下标为 4 (不包含 4)的元素
console.log(colors1)   // [ 'red', 'green', 'blue', 'yellow', 'purple' ]
console.log(colors2); // [ 'green', 'blue', 'yellow', 'purple' ]
console.log(colors3); // [ 'green', 'blue', 'yellow' ]
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const numbers = [1, 2, 3];
numbers.indexOf(3) // 2
numbers.indexOf(4) // -1
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const numbers = [1, 2, 3, 4, 5];
numbers.includes(4) // true
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const people = [
    {
        name: "Matt",
        age: 18
    },
    {
        name: "Nicholas",
        age: 19
    },
    {
        name: "Michael",
        age: 20
    }
];
people.find((element, index, array) => element.age < 20) // { name: "Matt", age: 18 }
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const values = [1, 2, 3, 4, 5];
values.reverse();
console.log(values); // 5,4,3,2,1
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function compare(value1, value2) {
    if (value1 < value2) {
        return -1;
    } else if (value1 > value2) {
        return 1;
    } else {
        return 0;
    }
}
const values = [0, 1, 5, 10, 15];
values.sort(compare);
console.log(values); // [0,1,5,10,15]
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const numbers = [4, 2, 5, 1, 3];
numbers.sort((a, b) => a - b); // a - b 为升序，b - a 为降序
console.log(numbers);// [1, 2, 3, 4, 5]
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const colors = ["red", "green", "blue"];
console.log(colors.join(",")); // red,green,blue
console.log(colors.join("||")); // red||green||blue
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const array = [1, 2, 3, 4, 5];

// 检查元素是否是偶数
const even = (element) => element % 2 === 0;

console.log(array.some(even)); // true
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const isBelowThreshold = (currentValue) => currentValue < 40;

const array1 = [1, 30, 39, 29, 10, 13];

console.log(array1.every(isBelowThreshold)); // true
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const array1 = ['a', 'b', 'c'];

array1.forEach(element => console.log(element));

// "a"
// "b"
// "c"
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const logArrayElements = (element, index, array) => {
  console.log('a[' + index + '] = ' + element);
};

// 注意：下标为 2 的元素会被跳过，因为该项为空
[2, 5,, 9].forEach(logArrayElements);
// a[0] = 2
// a[1] = 5
// a[3] = 9
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const words = ['spray', 'limit', 'elite', 'exuberant', 'destruction', 'present'];

const result = words.filter(word => word.length > 6);

console.log(result);
// ["exuberant", "destruction", "present"]
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const fruits = [undefined, 'apple', false, 'banana', 0, 'orange', null, ''];

const result = fruits.filter(Boolean);

console.log(result); // [ 'apple', 'banana', 'orange' ]
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const array1 = [1, 4, 9, 16];

const map1 = array1.map(x => x * 2);

console.log(map1);
// [2, 8, 18, 32]
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const icArray = [
  { id: 1, count: 10 },
  { id: 2, count: 20 },
  { id: 3, count: 30 }
];

// 假设现在有个需求，需要将 icArray 中每个对象的 id 的值作为新数组中每个对象的 key, 将每个对象的 count 的值作为新数组中每个对象的 value，则可以这样做：
const reformattedArray = icArray.map(({ id, count}) => ({ [id]: count }));

console.log('reformattedArray: ', reformattedArray); // [{1: 10}, {2: 20}, {3: 30}]
console.log('icArray', icArray); // icArray 还是原来的值： [{ id: 1, count: 10 },{ id: 2, count: 20 },{ id: 3, count: 30 }];
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