1. Search for files on GitHub repository
Press t
in the repo to enter search mode
for the project’s file structure
2. Highlight/Reply shortcut in Github
- When in an issue, Highlight the line which needs a reply.
- Then press
r
to reply to that from the comment
3. Shortcut to use Lodash
- Go to the Lodash homepage
- Open devtools
- Lodash library is available for use from
_
variable
4. Nullish coalescing operator
const height = 0;
console.log(height || 100); // 100
console.log(height ?? 100); // 0
Nullish coalescing operator
(??) returns the right-hand side value only if the left-hand side value is undefined
or null
5. Convert a number from decimal to binary
toString()
can be used to convert numbers to different bases. It takes a param, which specifies the base to convert to.
To convert a number to binary, the base would be 2
.
const decimal = 5;
const binary = decimal.toString(2);
console.log(binary); // 101
6. Add Properties to functions
function greetings() {
console.log("hello world");
greetings.counter++;
}
greetings.counter = 0;
greetings();
greetings();
console.log(`Called ${greetings.counter} times`); // Called 2 times
7. Change array size using the length property
const arr = [1, 2, 3, 4, 5];
arr.length = 2;
console.log(arr); // [1, 2]
8. Prevent an object’s properties value from updating
const obj = {name: 'Codedrops'};
console.log(obj.name); // Codedrops
/* Set the 'writable' descriptor to false for the 'name' key */
Object.defineProperty(obj, 'name', {
writable: false
});
obj.name = 'ABC';
console.log(obj.name); // Codedrops
9. Maps can store any type of key
const myMap = new Map([]);
const numberKey = 1;
const stringKey = "str";
const arrayKey = [1, 2, 3];
const objectKey = { name: "abc" };
myMap.set(numberKey, "Number Key");
myMap.set(stringKey, "String Key");
myMap.set(arrayKey, "Array Key");
myMap.set(objectKey, "Object Key");
myMap.forEach((value, key) => console.log(`${key} : ${value}`));
/*
Output:
1 : Number Key
str : String Key
1,2,3 : Array Key
[object Object] : Object Key
*/
10. null vs undefined
null
is a value, whereas undefined
is not.null
is like an empty box, and undefined
is no box at all.
ex.,
const fn = (x = 'default value') => console.log(x);
fn(undefined); // default value
fn(); // default value
fn(null); // null
When null
is passed, the default value is not taken, whereas when undefined
or nothing is passed the default value is taken.
That’s it for now.
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