this values in Observable The value of this has long been a weird detail of JavaScript - sometimes this is: An element, when the function is an event handler A class, if the function is attached to one The window object, if the function isn't attached to anything this is sort of special in Observable, too: it contains the previous returned value of a cell. Let's check this out by creating a cell that returns (this || 0) + 1 and making the cell evaluate 10 times by having it reference a generator that updates 10 times.
thisIcon
tenTimes = { for (let i = 0; i < 10; i++) { yield Promises.delay(1000); } }
{ tenTimes; return (this || 0) + 1; }
This as a pseudo-reducer In a way, using this lets you create reducer-like blocks. For example, let's collect input values as you type: type in the input below, and the array of values will include all of the intermediate states.
viewof input = html`<input />`
{ return (this || []).concat(input); }
import {thisIcon} from "@tmcw/icon-for-this-values-in-javascript"