JavaScript: Print all the methods in an JavaScript object

Last update on May 30 2022 10:00:41 (UTC/GMT +8 hours)

JavaScript Object: Exercise-11 with Solution

Write a JavaScript function to print all the methods in an JavaScript object.
Test Data:
console.log(all_properties(Array));
["length", "name", "arguments", "caller", "prototype", "isArray", "observe", "unobserve"]

Sample Solution: -

HTML Code:

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>JavaScript function to display all methods in a object.</title>
</head>
<body>

</body>
</html>

JavaScript Code:

function FindAllMethods(obj) {
    return Object.getOwnPropertyNames(obj).filter(function(property) {
        return typeof obj[property] == "function";
    });
}
//above code finds methods only
//Following code finds both properties and methods 
console.log(FindAllMethods(Math));
console.log(FindAllMethods(Array));
function all_properties(obj) 
{
 return Object.getOwnPropertyNames(obj);
}

console.log(all_properties(Math));

console.log(all_properties(Array));

Sample Output:

["abs", "acos", "acosh", "asin", "asinh", "atan", "atanh", "atan2", "ceil", "cbrt", "expm1", "clz32", "cos", "cosh", "exp", "floor", "fround", "hypot", "imul", "log", "log1p", "log2", "log10", "max", "min", "pow", "random", "round", "sign", "sin", "sinh", "sqrt", "tan", "tanh", "trunc"]
["isArray", "from", "of"]
["abs", "acos", "acosh", "asin", "asinh", "atan", "atanh", "atan2", "ceil", "cbrt", "expm1", "clz32", "cos", "cosh", "exp", "floor", "fround", "hypot", "imul", "log", "log1p", "log2", "log10", "max", "min", "pow", "random", "round", "sign", "sin", "sinh", "sqrt", "tan", "tanh", "trunc", "E", "LN10", "LN2", "LOG10E", "LOG2E", "PI", "SQRT1_2", "SQRT2"]
["length", "name", "prototype", "isArray", "from", "of"]

Flowchart:

Live Demo:

Click on the Codepen logo at the top right corner of the code snippet below to view the output.

See the Pen javascript-object-exercise-11 by w3resource (@w3resource) on CodePen.

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JavaScript: Tips of the Day

How to insert an item into an array at a specific index (JavaScript)?

What you want is the splice function on the native array object.

arr.splice(index, 0, item); will insert item into arr at the specified index (deleting 0 items first, that is, it's just an insert). In this example we will create an array and add an element to it into index 2:

var arr = []; arr[0] = "Jani"; arr[1] = "Hege"; arr[2] = "Stale"; arr[3] = "Kai Jim"; arr[4] = "Borge"; console.log(arr.join()); arr.splice(2, 0, "Lene"); console.log(arr.join());

Ref: https://bit.ly/2BXbp04