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July 30, 2020 02:08
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NodeJS | |
--- | |
Every file is a 'module' | |
console.log(`Hi ${this.name}!`); <-- `` Templating | |
Make sure to use the relative path when importing or node will think you are using the built in module | |
exports.sayHello = function() { | |
console.log("Hello!"); | |
}; | |
^ is same as: | |
module.exports = { | |
name: "Elie", | |
sayHello() { | |
console.log("Hello!"); | |
} | |
}; | |
Default module functions: | |
module.exports = function() { | |
console.log("I am the entire module!"); | |
}; | |
allows you to do --> evenMoreHelpers() | |
Destructuring Objects | |
--- | |
Allows for quick shorthand extraction of fields from objects. Example below | |
const obj = { first: 'Jane', last: 'Doe' }; | |
const {first: f, last: l} = obj; | |
//f = 'Jane'; l = 'Doe' | |
// {prop} is short for {prop: prop} | |
const {first, last} = obj; | |
// first = 'Jane'; last = 'Doe' | |
Destructuring Arrays | |
--- | |
const iterable = ['a', 'b']; | |
const [x, y] = iterable; | |
// x = 'a'; y = 'b' | |
Event Loop | |
--- | |
Stack which holds calls to be processed immediately | |
Async calls get added to the event loop | |
Event loop is a queue | |
Once the stack is cleared, calls from the event loop start getting executed in order of insertion (FIFO) | |
async.js | |
--- | |
shorthand for promise.all() <-- waiting for multiple promises to resolve before executing the callback function | |
Process Module | |
--- | |
Used to invoke CMD arguments | |
environment variables accessed using process.env | |
process.argv gives you command line arguments | |
process.env.ENV_VAR | |
Good read for event loop stuff | |
--- | |
https://blog.risingstack.com/node-hero-async-programming-in-node-js/ |
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