ES6 数组方法 forEach map filter find every some reduce

1. forEach

    const colors = ['red', 'blue', 'green']

    colors.forEach(function (params) {
      console.log(params)
    })

2. map  重构-返回数组

    const porducts = [
      {
        name: 'cucumber',
        type: 'vegetable',
        quantity: 0,
        price: 1
      },
      {
        name: 'cucumber',
        type: 'vegetable',
        quantity: 30,
        price: 10
      },
      {
        name: 'cucumber',
        type: 'fruit',
        quantity: 10,
        price: 16
      },
    ]

    porducts.map(function (params) {
      return params.price * 2
    })

    

3. filter   过滤-返回数组

    let porducts = [
      {
        name: 'cucumber',
        type: 'vegetable',
        quantity: 0,
        price: 1
      },
      {
        name: 'cucumber',
        type: 'vegetable',
        quantity: 30,
        price: 10
      },
      {
        name: 'cucumber',
        type: 'fruit',
        quantity: 10,
        price: 16
      },
    ]

   porducts.filter(function (product) {
      return product.type === 'fruit'
        && product.quantity > 0
        && product.price > 10
    })

4. find  过滤-返回数组

    let users = [
      {
        name: 'jill',
      },
      {
        name: 'alex',
        id: 0
      },
      {
        name: 'Bill',
      },
      {
        name: 'alex',
        id: 1
      }
    ]

    const use = users.find(function (params) {
      return params.name == 'alex'
    })

5. every  一假即假-返回Boolean

    let computer = [
      { name: 'apple', ram: 16 },
      { name: 'IBM', ram: 4 },
      { name: 'ACer', ram: 32 },
    ]

    const com = computer.every(function (params) {
      return params.ram > 16
    })

6. some  一真即真-返回Boolean

    let computer = [
      { name: 'apple', ram: 16 },
      { name: 'IBM', ram: 4 },
      { name: 'ACer', ram: 32 },
    ]

    const comt = computer.some(function (params) {
      return params.ram > 16
    })

7. reduce   返回值

1. 比较值获得最大值
    let porducts = [
      {
        name: 'cucumber',
        type: 'vegetable',
        quantity: 0,
        price: 21
      },
      {
        name: 'cucumber',
        type: 'vegetable',
        quantity: 30,
        price: 20
      },
      {
        name: 'cucumber',
        type: 'fruit',
        quantity: 10,
        price: 16
      },
    ]

    let prodList = porducts.reduce(function (first, last) {
      if (first < last.price) {
        first = last.price
      }
      return first
    }, 0)

2. 值与值想加
    let number = [10, 50, 30]
    let sum = 0

    let sumValue = number.reduce(function (sum2, number2) {
      // console.log(sum2)
      return sum2 + number2
    }, 100)