setState (and others) parameters format

[chenglou]

Currently accidentally using this.setState('title', 'Car') throws an unhelpful MERGE_CORE_FAILURE error. Would be nice to either throw a better error or accept this format.
Same goes for setProps, etc.

[petehunt]

Are you using the minified React package or unminified?

[chenglou]

minified, 0.3.3
Here's the error message for unminified:
Critical assumptions about the merge functions have been violated. This is the fault of the merge functions themselves, not necessarily the callers. react.js:4651

[petehunt]

Can you try with unminified? You should get a more helpful error message. If not, we have a bug.

[petehunt]

OK so that error message still sucks, but at least you're getting messages in the correct build. Thanks for the report!

[tomocchino]

@jordwalke will have some thoughts on this, since the proposed API doesn't support GCC key crushing, or whatever. I could go either way.. this API is more convenient and prevents an object allocation in the simple case (and it's familiar), but it also makes this function a bit more flexible, and I'm typically from the "constraints are liberating" camp.

[chenglou]

Just to clarify @tomocchino, I brought this habit over from Backbone and other libraries. I'm also in the same camp as you, and accepting this format was a mere idea. I'd much prefer a simple error message in the line of you need to pass an object for…, and then get over with this once and for all.

[piranha]

I would like to see setState accept both variants (either an object or a key with a value), it could look like that then:

  setState: function(key, value, callback) {
    var partialState;
    if (typeof key === 'string') { // {string, anything, fn}
        partialState = {};
        partialState[key] = value;
    } else { // {object, fn}
        partialState = key;
        callback = value;
    }

    // Merge with `_pendingState` if it exists, otherwise with existing state.
    this.replaceState(
      merge(this._pendingState || this.state, partialState),
      callback
    );
  },

I don't know if that (having two sets of arguments in a function) is acceptable style for React, but it is definitely used quite a bit in JS world. If that's acceptable, then another problem arises - how do I document that so that it renders nicely in documentation?

[zpao]

Based on our lack of movement on this and some of the discussion in the associated PR, I'm going to wontfix this. If it comes up again though I'm open for discussing further.