return uniqueArray; } 1. 2. 3. 4. 5. 6. 7. 如果数组的两项的ID相同,则删除掉。 有一种情况是,如果我们需要对对象所有属性进行比较,那么需要将对象转为字符串,然后再比较: function removeDuplicateObjectsById(array) { const seen = new Set(); const uniqueArray = array.filter(obj => { return...
1.利用Set()+Array.from() Set对象:是值的集合,你可以按照插入的顺序迭代它的元素。 Set中的元素只会出现一次,即Set中的元素是唯一的。 Array.from()方法:对一个类似数组或可迭代对象创建一个新的,浅拷贝的数组实例。 const result = Array.from(new Set(arr)) console.log(result) // [ 1, 2, 'abc...
The existingUsers object wouldn’t have duplicate keys either. Sets vs objects The main difference between the object (map, associative array), is that the Set is directly iterable. Which means it has a.forEachmethod, you can spread it into an Array (amongst other things). Set is easier ...
Write a JavaScript function to remove. 'null', '0', '""', 'false', 'undefined' and 'NaN' values from an array. Sample array : [NaN, 0, 15, false, -22, '',undefined, 47, null] Expected result : [15, -22, 47] Click me to see the solution 25. Sort Objects by Title Write...
Example 4: Grouping Objects by a property letpeople = [ {name:"John",age:21}, {name:"Oliver",age:55}, {name:"Michael",age:55}, {name:"Dwight",age:19}, {name:"Oscar",age:21}, {name:"Kevin",age:55}, ];functiongroupBy(objectArray, property){ ...
{// 'unused' is the only place where 'priorThing' is referenced,// but 'unused' never gets invokedif(priorThing) {console.log("hi"); } }; theThing = {longStr:newArray(1000000).join('*'),// Create a 1MB objectsomeMethod:function() {console.log(someMessage); } }; };setInterval...
具体请参考MDNhttps://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/some 总结一下: 后续补充:最近看很多小伙伴都在学习ES6,比如ES6中的map,在ES5中是怎么实现的呢? 1 /* 2 * MAP对象,实现MAP功能 3 * 4 * 接口:...
dead_code (default: true) -- remove unreachable code directives (default: true) -- remove redundant or non-standard directives drop_console (default: false) -- Pass true to discard calls to console.* functions. If you only want to discard a portion of console, you can pass an array li...
Duplicate entries may exist. Array.from(hamt.empty.values()) === []; Array.from(hamt.empty.set('a', 3).values()) === [3]; Array.from(hamt.empty.set('a', 3).values('b', 3).values()) === [3, 3]; hamt.forEach(f, map) map.forEach(f) Invoke function f for each ...
This is done by applying the desired effect to the layer's effect property as a string or an array of objects to set scale dependent effects. Notes Set featureEffect property if different effects need to be applied features that meet or fail a specified filter. If all of the following ...