Javascript 计算

求并集union:

var a = [34, 35, 45, 48, 49];
var b = [48, 55];
var union = [...new Set([...a, ...b])];
console.log(union);

方法二：

var array1 = ["Vijendra", "Singh"];
var array2 = ["Singh", "Shakya"];

console.log(array1.concat(array2));

参考：

https://stackoverflow.com/questions/3629817/getting-a-union-of-two-arrays-in-javascript

https://stackoverflow.com/questions/1584370/how-to-merge-two-arrays-in-javascript-and-de-duplicate-items

判断array1是否包含array2：

let array1 = [1,2,3],
    array2 = [1,2,3,4],
    array3 = [1,2];

let checker = (arr, target) => target.every(v => arr.includes(v));

console.log(checker(array2, array1));
console.log(checker(array3, array1));

参考：https://stackoverflow.com/questions/53606337/check-if-array-contains-all-elements-of-another-array

merge map：

/**
 * Overwrites obj1's values with obj2's and adds obj2's if non existent in obj1
 * @param obj1
 * @param obj2
 * @returns obj3 a new object based on obj1 and obj2
 */
function merge_options(obj1,obj2){
    var obj3 = {};
    for (var attrname in obj1) { obj3[attrname] = obj1[attrname]; }
    for (var attrname in obj2) { obj3[attrname] = obj2[attrname]; }
    return obj3;
}

参考：https://stackoverflow.com/questions/171251/how-can-i-merge-properties-of-two-javascript-objects-dynamically