基于一个公共键角度2合并2个阵列

这应该做你想要的:

const arr1 = [{"columnId":1,"type":"value 1"},{"columnId":2,"type":"value 2"}];
const arr2 = [{"columnId":1,"field":"field 1"},{"columnId":2,"field":"field 2"}];

const result = arr1.map(val => {
    return Object.assign({}, val, arr2.filter(v => v.columnId === val.columnId)[0]);
});

console.log(result);
// [{"columnId":1,"field":"field 1","type":"value 1"},{"columnId":2,"field":"field 2","type":"value 2"}]