Tuesday, December 21, 2021
Tuesday, December 14, 2021
Convert Number, String, Float and Format JSON
1) Convert to String
To quickly convert a number to a string, we can use the concatenation operator (+) plus followed by an empty set of quotation marks "" .
let val = 1 + "";
console.log(val); // Result: "1"
console.log(typeof val); // Result: "string"
2) Convert to Number
The opposite can be quickly achieved using the addition operator + .
let int = "15";
int = +int;
console.log(int); // Result: 15
console.log(typeof int); Result: "number"
This may also be used to convert Booleans to numbers, as below:
console.log(+true); // Return: 1
console.log(+false); // Return: 0
3)Quick Float to Integer
If you want to convert a float to an integer, you can use Math.floor() , Math.ceil() or Math.round() . But there is also a faster way to truncate a float to an integer using |, the bitwise OR operator.
console.log(23.9 | 0); // Result: 23
console.log(-23.9 | 0); // Result: -23
4)Format JSON Code
Lastly, you may have used JSON.stringify before, but did you realise it can also help indent your JSON for you?
The stringify() method takes two optional parameters: a replacer function, which you can use to filter the JSON that is displayed, and a space value.
The space value takes an integer for the number of spaces you want or a string (such as '\t' to insert tabs), and it can make it a lot easier to read fetched JSON data.
console.log(JSON.stringify({ alpha: 'A', beta: 'B' }, null, '\t'));
// Result:
// '{
// "alpha": A,
// "beta": B
// }'
Monday, December 13, 2021
Get Query Params
window.location object has a bunch of utility methods and properties. We can get information about the protocol, host, port, domain, etc from the browser URLs using these properties and methods.
var args = window.location.search
let data = new URLSearchParams(location.search).get('reqId');
console.log(data)
Few Javascript or JQuery Tricks for array and operators
1) Empty an array
var arr = [10 , 20 , 30 ];
arr.length = 0; // arr will be equal to [].
2) Truncate an array using length
Like the previous example of emptying an array, we truncate it using the length property.
var arr = [10, 20, 30, 40, 50, 60, 70, 80, 90];
arr.length = 4; // arr will be equal to [10, 20, 30, 40].
As a bonus, if you set the array length to a higher value, the length will be changed and new items will be added with undefined as a value. The array length is not a read only property.
arr.length = 10; // the new array length is 10
arr[arr.length - 1] ; // arr [10, 20, 30, 40, 50, 60, 70, 80, 90, undefined];
3)Use logical AND/ OR for conditions
var foo = 10;
foo == 10 && doSomething(); // is the same thing as if (foo == 10) doSomething();
foo == 5 || doSomething(); // is the same thing as if (foo != 5) doSomething();
4) Comma operator
var a = 10;
var b = ( a++, 99 );
console.log(a); // a will be equal to 10
console.log(b); // b is equal to 99
5) Swap variables
let v1 = 'value 1';
let v2 = 'value 2';
[v1,v2] = [v2, v1];
console.log(v1, v2);
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