Coding Recipes
  • Introduction
  • Welcome
    • Introduction
  • SEO Recipes
    • How can I add more metadata to my page to improve SEO?
  • Console Recipes
    • How to colour text in the browser and server console
  • Array Recipes
    • How can I filter out falsey values?
  • Object Recipes
    • How can I clone an object?
    • How can I destructure an object?
    • How can I pretty-print an object?
    • How can I conditionally add a key-value into an object?
    • How can I pull keys, values and entries off an object?
    • How can I build an object with computed property names?
    • What does 'this' mean?
    • How does inheritance work between objects?
    • How can I build a query string from an object?
    • How to instantiate a class using an object of that class?
    • Nested Ternaries vs Switch Statements
  • String Recipes
    • How can I tokenise a string of values into an array?
    • How can I parse a template string into its constant and variable parts?
  • Function Recipes
    • How to find out where your function is being called from
    • How can I simplify argument validation in a function?
    • How would I handle errors?
    • What types of functions can I rebind 'this' on?
    • How can I find out the length of a function's parameter list?
  • Asynchronous Recipes
    • How do I use fetch?
    • How do I use Promises?
    • How do I use async and await?
    • How do I use jQuery to make async calls?
    • How can I use Axios to make async calls?
    • How can I use Web Workers to achieve parallelism?
  • React Recipes
    • How can I DRY-up passing props to a React component?
    • How can I conditionally render JSX?
    • What are the different types of PropTypes I can use?
    • How can I handle a component throwing an uncaught exception?
    • How can I use context to selectively pass data down a component hierarchy? (2 approaches)
    • How to define a Higher Order Component (HOC) in React
    • What are the different lifecycle methods in React?
    • HOCs vs. RenderProps - How To Share State
    • How to use refs in React (3 Approaches)
  • React Router Recipes
    • How do I install react router 4 as an application dependency
    • What are the different types of routes that I can create?
    • How can I navigate between different types of routes?
    • How can I style the link for the route that is currently active?
    • How can I pass parameters to my routes?
    • How can I match routes by making sure parameters match a specific format?
    • How can I parse query parameters from a route?
    • How can I define a default catch-all route?
    • How can I render multiple components for a single route?
    • How can I create nested routes?
    • How can I redirect from one route to another route?
    • How can I intercept transitioning from one route to another route?
  • Conditional Logic Recipes
    • How can I avoid using multiple if..else if...else if style code?
    • How can I check which of several booleans is true?
  • RxJS Recipes
    • How can I subscribe to a series of numbers?
    • How can I subscribe to an array of numbers?
    • How can I transform an array of numbers?
    • How can I listen to double-click events?
    • How can I create an Observable from something else?
  • Redux Recipes
    • Redux - Architecture
    • React-Redux - Architecture
    • How to define custom middleware for Redux
    • How to enable Hot Module Reloading for a React-Redux-Webpack application
  • GraphQL
    • How can I create a simple GraphQL client and server?
    • Stuff
Powered by GitBook
On this page

Was this helpful?

  1. Function Recipes

How can I find out the length of a function's parameter list?

// How to find out length of a function's parameter list
const add = (x, y) => x + y
console.log(`The add() function takes ${add.length} arguments`)
PreviousWhat types of functions can I rebind 'this' on?NextHow do I use fetch?

Last updated 5 years ago

Was this helpful?