preact/debug error only in v8.2.6

[whitetrefoil]

After upgraded my project from [email protected] to v8.2.6, I had this error when loading the page:

debug.js:49 Uncaught TypeError: Cannot set property render of #<Object> which has only a getter

// debug.js:L49
preact.render = function (vnode, parent, merge) {

If I stop requiring preact/debug it would be OK. I require it like this:

window['Promise'] = require('promise-polyfill')

if (process.env.ENV === 'production') {
  // Production
} else {
  // Development
  Error['stackTraceLimit'] = Infinity
  require('preact/debug')
}

When using v8.2.5 it was all good.

I'm using only preact with webpack@2 without preact-compat or any react related stuff.

[brunomolteni]

I'm also having the same issue

[Kanaye]

The render() override was added in preact 8.2.6 or to be specific in #885.
The problem is the ES module exports are "read only" per rfc.
Webpack defines ES module exports as getter only properties and that is why this override fails.

I'm not sure what could be a viable long term solution for this.

For now you can just add

  'preact$': 'preact/dist/preact.js'

to the alias section of your webpack config.
This will ensure that webpack uses the commonjs version of preact and therefore the exports won't be readonly.

[NekR]

I'm not sure what could be a viable long term solution for this.

The solution would be to not use require('preact') in preact/debug.

[NekR]

The solution in original preact/debug was to use require('../') and override preact.h, when we changed to using preact.options.vnode it was possible to just use require('preact').

I'm not sure, but there possible could be an issue with webpack if we are going to use require('../') or require('preact/dist/preact.js') -- it may include the code twice.

[NekR]

@whitetrefoil you don't have to guard preact/debug with process.env.NODE_ENV guard, it does so for you automatically. That's why it's better to use than preact/devtools.

[developit]

Might be worth just wrapping the render override in a try/catch. We can inject it in Webpack 2.

[NekR]

That's webpack 2+, not only wepback 2.

[NekR]

The thing what you did is not a fix.

[developit]

We can't really work around this though - the object returned from require('preact') is immutable in Webpack 2+.

[NekR]

I think there should be a way. I'll take a look into that later this week.

[paranoidjk]

came across same problem, i think we should at least add some notice in Readme.