Pretty JSON formatter

[liuzhe-lz]

This util formats JSON basing on expected width.

Take following object as example:

{
    "batch_size": {"_type": "choice", "_value": [16, 32, 64, 128]},
    "hidden_size": {"_type": "choice", "_value": [128, 256, 512, 1024]},
    "lr": {"_type": "choice", "_value": [0.0001, 0.001, 0.01, 0.1]},
    "momentum": {"_type": "uniform", "_value": [0, 1]}
}

When the width is 60, it will be formatted as:

{
    "batch_size": {
        "_type": "choice",
        "_value": [16, 32, 64, 128]
    },
    "hidden_size": {
        "_type": "choice",
        "_value": [128, 256, 512, 1024]
    },
    "lr": {
        "_type": "choice",
        "_value": [0.0001, 0.001, 0.01, 0.1]
    },
    "momentum": {
        "_type": "uniform",
        "_value": [0, 1]
    }
}

When the width is 40, it will be:

{
    "batch_size": {
        "_type": "choice",
        "_value": [
            16,
            32,
            64,
            128
        ]
    },
    "hidden_size": {
        "_type": "choice",
        "_value": [
            128,
            256,
            512,
            1024
        ]
    },
    "lr": {
        "_type": "choice",
        "_value": [
            0.0001,
            0.001,
            0.01,
            0.1
        ]
    },
    "momentum": {
        "_type": "uniform",
        "_value": [
            0,
            1
        ]
    }
}

The _value arrays will always get collapsed or expanded together, since the util thinks they are "similar".

[ultmaster]

Can we expose the interface of indent width?

[liuzhe-lz]

As long as it's not configurable in web UI, I think we can make life easier.

[ultmaster]

I thought it is to call JSON.stringify and remove some blanks and newlines. Turned out it was a whole new stringifier.

[QuanluZhang]

@Lijiaoa please help review

[Lijiaoa]

could you remove yarn.lock changes? Because PR #2866 had same changes.

[liuzhe-lz]

yarn.lock is automatically modified on build.
I wonder why it's not committed by the PR which changes package.json...

[Lijiaoa]

emmm, the changes of yarn.lock should be committed by PR which changes package.json. but PR #2866 had done this with other dev update. I think #2866 should be merged into master. so I suggest not upload yarn.lock changes in this PR.

[Lijiaoa]

PR #2880 had modifiy the rule no-use-before-define