no-this-assign-in-render.md

Disallows assignments to members of this in render methods (no-this-assign-in-render)

Assignments to this in the render method of a LitElement are generally a mistake since it should ideally act like a pure function.

Property updates should usually happen in the other lifecycle methods (e.g. updated) or in event handlers.

Rule Details

This rule disallows assigning to this in the render method.

The following patterns are considered warnings:

render() {
  this.prop = 5;
}

The following patterns are not warnings:

render() {
  const prop = 5;
}

updated() {
  this.prop = 5;
}

When Not To Use It

If you have non-observed properties you wish to update per render, you may want to disable this rule.