JavaScript: Compare two objects to determine if the first one contains equivalent property values to the second one, based on a provided function

JavaScript fundamental (ES6 Syntax): Exercise-179 with Solution

Write a JavaScript program to compare two objects to determine if the first contains equivalent property values to the second one. This is based on a provided function.

• Use Object.keys() to get all the keys of the second object.
• Use Array.prototype.every(), Object.prototype.hasOwnProperty() and the provided function to determine if all keys exist in the first object and have equivalent values.
• If no function is provided, the values will be compared using the equality operator.

Sample Solution:

JavaScript Code:

//#Source https://bit.ly/2neWfJ2 
const matchesWith = (obj, source, fn) =>
  Object.keys(source).every(
    key =>
      obj.hasOwnProperty(key) && fn
        ? fn(obj[key], source[key], key, obj, source)
        : obj[key] == source[key]
  );
const isGreeting = val => /^h(?:i|ello)$/.test(val);

console.log(matchesWith(
  { greeting: 'hello' },
  { greeting: 'hi' },
  (oV, sV) => isGreeting(oV) && isGreeting(sV)
));

Sample Output:

true

Flowchart:

Live Demo:

See the Pen javascript-basic-exercise-179-1 by w3resource (@w3resource) on CodePen.

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