quick-lint-js

Find bugs in JavaScript programs.

E0063: missing operator between expression and arrow function

The left-hand side of => must be a list of parameters. It is a syntax error if the left-hand side looks like a function call:

let fs = require("fs");
let path = process.argv[2];
fs.readFile(path (err, data) => {
  console.log(data);
});

To fix this error, make the left-hand side of => valid by adding an operator (usually ,) before the parameter list:

let fs = require("fs");
let path = process.argv[2];
fs.readFile(path, (err, data) => {
  console.log(data);
});

Documentation for other errors