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JavaScript: Retrieve all the names of object's own and inherited properties

JavaScript Object: Exercise-13 with Solution

Write a JavaScript function to retrieve all the names of object's own and inherited properties.

Sample Solution: -

HTML Code:

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>JavaScript function to retrieve all the names of object's own and inherited properties.</title>
</head>
<body>

</body>
</html>

JavaScript Code:

function allKeys(obj) {
    if (!isObject(obj)) return [];
    var keys = [];
    for (var key in obj) keys.push(key);
    return keys;
}
function isObject(obj) 
{
    var type = typeof obj;
    return type === 'function' || type === 'object' && !!obj;
  }
function Student(name) {
  this.name = name;
}
Student.prototype.rollno = true;
console.log(allKeys(new Student("Sara")));

Sample Output:

["name","rollno"]

Flowchart:

Flowchart: JavaScript:- Retrieve all the names of object's own and inherited properties

Live Demo:

See the Pen javascript-object-exercise-13 by w3resource (@w3resource) on CodePen.


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Previous: Write a JavaScript function to parse an URL.
Next: Write a JavaScript function to retrieve all the values of an object's properties.

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JavaScript: Tips of the Day

Creates an object composed of the properties the given function returns truthy for. The function is invoked with two arguments: (value, key)

Example:

const tips_composed = (obj, fn) =>
  Object.keys(obj)
    .filter(k => fn(obj[k], k))
    .reduce((acc, key) => ((acc[key] = obj[key]), acc), {});

console.log(tips_composed({ p: 2, q: '4', r: 6 }, x => typeof x === 'number'));

Output:

[object Object] {
  p: 2,
  r: 6
}