# E0160: unexpected '=>'; expected parameter for arrow function, but got an expression instead

The left-hand side of `=>` must be a list of parameters. It is a syntax error if the left-hand side is instead an expression (such as a property access or a function call):

    if (this.mapSize => this.capacity) {
      throw new Error("too many items");
    }

    let fs = require("fs");
    let path = process.argv[2];
    fs.mkdir(path () => console.log("done"));

To fix this error, replace `=>` with the intended operator, such as `>=`:

    if (this.mapSize >= this.capacity) {
      throw new Error("too many items");
    }

Alternatively, 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.mkdir(path, () => console.log("done"));

Introduced in quick-lint-js version 0.3.0.

Documentation for other errors