JavaScript: Create a new object from the combination of two or more objects
JavaScript fundamental (ES6 Syntax): Exercise-178 with Solution
Write a JavaScript program to create a new object from the combination of two or more objects.
- Use Array.prototype.reduce() combined with Object.keys() to iterate over all objects and keys.
- Use Object.prototype.hasOwnProperty() and Array.prototype.concat() to append values for keys existing in multiple objects.
Sample Solution:
JavaScript Code:
//#Source https://bit.ly/2neWfJ2
const merge = (...objs) =>
[...objs].reduce(
(acc, obj) =>
Object.keys(obj).reduce((a, k) => {
acc[k] = acc.hasOwnProperty(k) ? [].concat(acc[k]).concat(obj[k]) : obj[k];
return acc;
}, {}),
{}
);
const object = {
a: [{ x: 2 }, { y: 4 }],
b: 1
};
const other = {
a: { z: 3 },
b: [2, 3],
c: 'foo'
};
console.log(merge(object, other));
Sample Output:
{"a":[{"x":2},{"y":4},{"z":3}],"b":[1,2,3],"c":"foo"}
Flowchart:

Live Demo:
See the Pen javascript-basic-exercise-178-1 by w3resource (@w3resource) on CodePen.
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Next: Write a JavaScript program to compare two objects to determine if the first one contains equivalent property values to the second one, based on a provided function.
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