# Source: https://github.com/quick-lint/quick-lint-js/blob/master/docs/errors/E0063.md

# 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:

```javascript
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:

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

Introduced in quick-lint-js version 0.2.0.