您可以使用Array#map以扩展语法合并相同索引处的元素。

let a = [{name: 'asha', age:20, mother: "sushi", father: "Nick"}], b = [{class: "10th", Sub: "science", Marks: 30, }]
let res = a.map((x, i) => ({...x, ...b[i]}));
console.log(res);

假设两个数组具有相同的长度，则可以对相应的元素使用带有spread运算符的for循环

const combined = [];
for(let i...) {
  combined.push({ ...arr1[i], arr2[i]});
}

可以按如下方式使用Array#forEach：

const
     a = [{name: 'asha', age:20, mother: "sushi", father: "Nick"}],
     b = [{class: "10th", Sub: "science", Marks: 30}],
     c = [];
     
a.forEach((val, i) => c.push({...val,...b[i]}));

console.log( c );