consistent-this

Code that saves this for a nested function calls the variable that, self, me or vm. If you use one name everywhere, you know what the variable holds without looking up its declaration.

The rule reports this assigned to any other name. It also reports the chosen name when it holds something other than this. The default name is that.

Configure

Off by default. To turn it on:

[lint.rules]
"consistent-this" = "error" # or "warn"

Every option, set to its default:

[lint.rules]
"consistent-this" = ["error", "that"]

Examples

Reported:

function Timer() {
  const self = this;
  setInterval(function () {
    self.tick();
  }, 1000);
}

const that = document.body;

Not reported:

function Timer() {
  const that = this;
  setInterval(function () {
    that.tick();
  }, 1000);
}

Destructuring isn't an alias, so it's allowed:

function Timer() {
  const { interval, tick } = this;
  setInterval(tick, interval);
}

Options

The options are one or more names you allow:

[lint.rules]
consistent-this = ["error", "self", "vm"]

function Timer() {
  const self = this;
  setInterval(function () {
    self.tick();
  }, 1000);
}

When not to use it

An arrow function uses the surrounding code's this, so new code rarely needs an alias at all.