/
index.js
45 lines (38 loc) · 1.33 KB
/
index.js
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const EventEmitter = require('events')
module.exports = function watchify (so) {
Object.defineProperty(so, '_emitter', {
writable: true, enumerable: false, configurable: false, value: new EventEmitter()
})
Object.defineProperty(so, '_originalWrite', {
writable: true, enumerable: false, configurable: true, value: so.write
})
Object.defineProperty(so, '_emit', {
writable: true, enumerable: false, configurable: false, value: so._emitter.emit
})
so.write = function (oid, iid, rid, value, opt, callback) {
const self = this
if (typeof opt === 'function') {
callback = opt
opt = undefined
}
this.read(oid, iid, rid, (er, oldValue) => {
self._originalWrite(oid, iid, rid, value, opt, (err, currentValue) => {
if (!err && (currentValue !== undefined)) {
if (currentValue !== oldValue) {
const iPath = `${oid}/${iid}/`
self._emit(iPath, {
iPath, rid, cVal: currentValue, pVal: oldValue
})
self._emit(`${oid}/${iid}/${rid}`, currentValue, oldValue)
}
}
callback(err, currentValue)
})
})
}
so.onChange = so._emitter.on
so.onChangeOnce = so._emitter.once
so.removeListener = so._emitter.removeListener
so.removeAllListeners = so._emitter.removeAllListeners
return so
}