default function parameters

Default Function Parameters

ES6 provides a new syntax to set default values for function arguments.

Function parameters are undefined unless an argument value is provided when the function is called. ES6 now allows function parameters to be configured with a custom default value.

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const greeter = (name = 'user', age) => {
 console.log('Hello ' + name)
}
greeter('Andrew') // Will print: Hello Andrew
greeter() // Will print: Hello user

This syntax can also be used to provide default values when using ES6 destructuring. The transaction function below shows this off by providing a default value for stock

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const transaction = (type, { label, stock = 0 } = {}) => {
 console.log(type, label, stock)
}
transaction('order')

reference : Udemy ‘The Complete Node.js Developer course’ by Andrew Mead