JS遍历的一些测试

测试代码

<template>
    <div class="container">
        <span>This Test</span>
    </div>
</template>

<script>
    export default {
        name: "Test",
        data() {
            return {
                arr: [{
                    a: 111,
                    b: 222
                }, {
                    c: 333,
                    d: 444
                }]
            }
        },
        mounted() {
            console.log(this.arrfor())
            console.log(this.arrforof())
            this.arrfilter()
            this.arrsome()
            console.log(this.arrforeach())
            console.log(this.arrmap())
            console.log(this.arrfind())
        },
        methods: {
            arrfor() {
                var len = this.arr.length
                for (var j = 0; j < len; j++) {
                    if (this.arr[j].a == 111) {
                        return 'arrfor success'
                    }
                }
            },
            arrforof() {
                for (var item of this.arr) {
                    if (item.a == 111) {
                        return 'forof success'
                    }
                }
            },
            arrfilter() {
                console.log(this.arr.filter(item => {
                    return item.c == 333
                }))
            },
            arrsome() {
                console.log(this.arr.some(item => {
                    if (item.a == 111) {
                        return 'arrsome success'
                    }
                }))
            },
            arrforeach() {
                this.arr.forEach(item => {
                    if (item.a == 111) {
                        return 'arrforeach success'
                    }
                })
            },
            arrmap() {
                this.arr.map(item => {
                    if (item.a == 111) {
                        return 'map success'
                    }
                })
            },

            arrfind() {
                this.arr.find((item) => {
                    item.a == 111
                })
            }

        },
    }
</script>

<style scoped>

</style>

测试结果

 

 

仅for和forof能正确return

filter返回新数组，判断结果为true则加入新数组，否则过滤

some返回true时跳出整个循环 ruturn 类型仅能为 Boolean