Getting URL Parameters on GatsbyJS

Use props.location, introduced in Gatsby v2. It's made available by @reach/router to all components via props.

function Component(props) {
  // use props.location...
  return ...
}

Use URLSearchParams.get() as described on MDN:

// Get the location object that is implicitly passed as props 
// for every page in the `pages` folder
const Index = ({ location }) => { 
  console.log(location); // inspect location for yourself

  // the parameter to return for URL. Example: 
  // https://localhost:8000/?parameter1=firstParam&parameter2=secondParam
  const params = new URLSearchParams(location.search);
  const parameter1 = params.get("parameter1");
  const parameter2 = params.get("parameter2");

  console.log(parameter1); // -> "firstParam"
  console.log(parameter2); // -> "secondParam"
  // ...

---

Alternative: package query-string

yarn add query-string or npm i --save query-string

import * as queryString from "query-string";

// Get the location object that is implicitly passed as props 
// for every page in the `pages` folder
const Index = ({ location }) => { 
  console.log(location); // inspect location for yourself

  // query-string parses the parameters that are contained in the location object
  const { parameter1, parameter2 } = queryString.parse(location.search);

  console.log(parameter1);
  console.log(parameter2);
  // ...