閉包舉例：

function closure(){var innerVariable = 'inner';function innerFn(){ return innerVariable;}return innerFn(); } var innerVariable = 'defined in outer'; var outerVariable = closure(); console.log(outerVariable);

測試字符串是否回文：

function testString(testString){var length = testString.length;for(var i = 0; i <= (length-1)/2;i++){if(testString[i] !== testString[length - 1 - i]){return false;}}return true; }

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var isPalindrome = function(testString){var length = testString.length;var splittedArray = testString.split('');return splittedArray.join() == splittedArray.reverse().join(); }console.log(isPalindrome('1221')); console.log(isPalindrome('1344'))

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var isPalindrome = function(testString){var length = testString.length;for(var i = length - 1,j=0; i >= 0;i--){
　　　　 if(i <= j){
　　　　　　return true;
　　　　　}if(testString[i] == testString[j++]){continue;}else{return false; } }return true; }console.log(isPalindrome('121')) console.log(isPalindrome('1221')) console.log(isPalindrome('1234'))

?

function isPalindrome(testString){var reversedString = '';for(var i = testString.length; i >= 0; i-- ){reversedString += testString.charAt(i);}if(reversedString == testString){return true;}else{return false;} }console.log(isPalindrome('121')); console.log(isPalindrome('1213'));

?

數組去重：

function uniqueArray(array){ var isArray = function(array){ var isArray = Object.prototype.toString.call(array) == "[object Array]"; if(isArray){ console.log(array + ' is an array'); } else{ console.log(array + ' is not an array'); } return isArray; } if(!!isArray(array)){ var length = array.length; for(var i = length - 1; i >=0; i--){ if(i == 0){ continue; } for(var j = i - 1; j>=0;j--){ if(array[j] == array[i]){ console.log(array[j]); array.splice(j,1); } console.log(array) } } console.log(array); return array; }else{ return null; } }var testArray = [12,123,34,12]; testArray = uniqueArray(testArray); console.log(testArray)

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Curry Function:

function curry(fn,arg1,arg2){ var toArray = function(args,n){return Array.prototype.slice.call(args,n);} var requiredArgsLength = fn.length; console.log('requiredArgsLength:' + requiredArgsLength); if((arguments.length - 1) < requiredArgsLength){ console.log('lack of arguments'); var partialArgs = toArray(arguments,1); console.log(partialArgs); return function(){ var args = partialArgs.concat(toArray(arguments,0)); console.log('completeArgs:' + args); return fn.apply(null,args); } } else{ return fn.apply(null,toArray(arguments,1));} }function add(arg1,arg2){ return arg1 + arg2; } console.log(curry(add,4,5)) var curriedFn = curry(add,4); curriedFn(5)

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Fibnacci:

function fib(n){if(n==1 || n ==0) {return n;} else{return n*fib(n-1)}}

?

//indexof test

var testNum = 9;

~testNum + 1 == -testNum;

?

?

查找特定tag：

function tagCounter(tagName){
switch(tagName.toLowerCase()){
case 'p': return document.getElementsByTagName('p');
case 'a': return document.getElementsByTagName('a');
}
}

實現繼承：

var parent = function(){this.parentName = 'parent';} var child = function(){this.childName = 'child'} child.prototype = new parent(); var childInstance = new child(); childInstance.childName childInstance.parentName childInstance.__proto__ instanceof parent

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閉包：

function outerFunction(){
var innerValue = 10;
return function(){
return innerValue;
}
}

var outerValue = outerFunction()();
console.log(outerValue);

利用構造函數實現繼承：

var parentObject = {parentName:'parent'}
var childObject = {childName: 'child'}
var tempFunction = function(){}
tempFunction.prototype = parentObject
childObject = new tempFunction
childObject.parentName

比較對象是否相等：

function isEqualObject(src,obj){ var srcJSONString = JSON.stringify(src) var objJSONString = JSON.stringify(obj) if(!( (/:/.test(srcJSONString)).length == (/:/.test(objJSONString)).length){return false;} if(keys(src) != keys(obj)){ return false; } for(var i in src){ if(src[i] == obj[i]){ continue;} else{return false}} return true; }function keys(obj){ var keysArray = []; for(var i in obj){ if(obj.hasOwnProperty(i)){ keysArray.push(i) } else{continue;} } }

underscorejs自己實現：

function delay(fn,milliseconds){setTimeout(fn,milliseconds)}

多態：

function multiple(){
if(arguments.length == 0){
console.log('please provide params');
return false;
}
else if(arguments.length == 1){
return arguments[0]
}
else if(arguments.length == 2){
return arguments[0]+ arguments[1]
}
}

console.log(multiple())
console.log(multiple(2))
console.log(multiple(2,3))

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throttled Version:

var clickHandler = function(e){console.log(e);console.log(new Date())}

var throttledClickHandler = _.throttle(clickHandler,2000)

window.addEventListener('click',throttledClickHandler)

?

debounce version:

var clickHandler = function(e){console.log(new Date())}

var debouncedClickHandler = _.debounce(clickHandler,2000)

window.addEventListener('click',debouncedClickHandler)

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extend example:

?

var testPropertyObject = {name:'test'}
var targetObject = {testProperty:testPropertyObject}
var destinationObject = _.extend(targetObject,{extendProperty:'extended'})
destinationObject.testProperty == testPropertyObject
destinationObject.testProperty === testPropertyObject

綁定多個事件：

$('.noresult').on({'click':function(e){console.log('click')},'touchstart':function(e){console.log('touchStart')}})

?

取消多個事件的綁定：

$('.noresult').on('touchstart',function(e){console.log('touchstart')})

$('.noresult').on('click',function(e){console.log('click')})

$('.noresult').off(['click','touchstart'])

轉載于:https://www.cnblogs.com/social/p/4325226.html

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