前端常见面试题（二十一）@郝晨光

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URL转对象

let url = 'https://www.baidu.com?name=郝晨光&age=24&sex=男';
function getURLParams(url) {
    let paramsStr = url.split('?')[1];
    let paramsArr = paramsStr.split('&');
    let result = {};
    for(let i = 0; i < paramsArr.length; i++) {
        let params = paramsArr[i].split('=');
        result[params[0]] = params[1];
    }
    return result;
}
console.log(getURLParams(url));

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不使用循环返回数组

let num = 10;
function getArr(num) {
    let arr = [];
    return (function(){
        arr.unshift(num);
        num--;
        if(num > 0) {
            arguments.callee();
        }
        return arr;
    })()
}
console.log(getArr(num));

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事件委托的实现

    

        哈哈
    

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冒泡排序

let arr = [3,21,5,6,3,2,4,7,3,46,8,43];
function sort(arr) {
    for(let i = 0; i < arr.length; i++) {
        for(let j = i + 1; j < arr.length; j++) {
            if(arr[i] > arr[j]) {
                let temp = arr[i];
                arr[i] = arr[j];
                arr[j] = temp;
            }
        }
    }
}
sort(arr);
console.log(arr);

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输出字符串中出现次数最多的字符及其出现次数

let str = 'asdfghjasdfghjassdasasdasdaa';
function getMaxWord(str) {
    let obj = {};
    let result = {
        word: '',
        count: 0
    };
    for(let i = 0; i < str.length; i++) {
        if(obj[str[i]]) {
            obj[str[i]]++;
        }else {
            obj[str[i]] = 1;
        }
    }
    for(let i in obj) {
        if(result.count < obj[i]) {
            result.word = i;
            result.count = obj[i];
        }
    }
    return result;
}
console.log(getMaxWord(str));

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判断是否是回文

let str = '我爱妈妈，妈妈爱我';
function palindrome(str) {
    return str === str.split('').reverse().join('');
}
console.log(palindrome(str));

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千分符，将数字格式化成RMB格式

let rmb = 1234567890;
function toRMB(num) {
    let str = num.toString();
    let arr = str.split('').reverse();
    let result = [];
    for(let i = 0; i < arr.length; i ++) {
        if(i % 3 === 0 && i !== 0) {
            result.push(',')
        }
        result.push(arr[i]);
    }
    return result.reverse().join('');
}
console.log(toRMB(rmb));

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字符串转驼峰

let str = 'get-element-by-id';
function toHumpName(str) {
    return str.replace(/\-\w/g, ([,word]) => {
        return word.toUpperCase()
    })
}
console.log(toHumpName(str));

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找出数组最大的差值，最大值减最小值的差

let arr = [1, 2, 5, 65, 90, 101, 32, 54, 43, 53];
function maxDifference(arr) {
    let min = Math.min.apply(null, arr);
    let max = Math.max.apply(null, arr);
    return max - min;
}
console.log(maxDifference(arr));

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数组去重

let arr = [1, 2, 3, 4, 5, 1, 2, 3, 5, 6, 7, 8, 1, 5];
function noRepeat(arr) {
    let result = [];
    for(let i = 0; i < arr.length; i++) {
        if(!result.includes(arr[i])) {
            result.push(arr[i]);
        }
    }
    return result;
}
console.log(noRepeat(arr));

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获取非行间样式

function getStyle(el, attr) {
    return el.current? el.currrent[attr] : getComputedStyle(el)[attr];
}

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斐波那契数列

function fbnq(n) {
    return n < 2 ? n : arguments.callee(n - 1) + arguments.callee(n - 2);
}
function fbnq2(n) {
    let num1 = 1;
    let num2 = 1;
    let result = num2;
    for(let i = 2; i < n; i++) {
        result = num1 + num2;
        num1 = num2;
        num2 = result;
    }
    return n < 2 ? n : result;
}
let arr = [];
let arr2 = [];
for(let i = 0; i <= 10; i++) {
    arr.push(fbnq(i));
    arr2.push(fbnq2(i));
}
console.log(arr);
console.log(arr2);

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如果本文对您有帮助，可以看看本人的其他文章:
前端常见面试题（二十）@郝晨光
前端常见面试题（十九）@郝晨光
前端常见面试题（十八）@郝晨光

结言

感谢您的查阅，本文由郝晨光整理并总结，代码冗余或者有错误的地方望不吝赐教；菜鸟一枚，请多关照