CasperSecurity
import { evaluateLater } from '../evaluator'
import { effect } from '../reactivity'
import { magic } from '../magics'
magic('watch', el => (key, callback) => {
let evaluate = evaluateLater(el, key)
let firstTime = true
let oldValue
effect(() => evaluate(value => {
// JSON.stringify touches every single property at any level enabling deep watching
JSON.stringify(value)
if (! firstTime) {
// We have to queue this watcher as a microtask so that
// the watcher doesn't pick up its own dependencies.
queueMicrotask(() => {
callback(value, oldValue)
oldValue = value
})
} else {
oldValue = value
}
firstTime = false
}))
})