Suggestion: Generate Param values given a JSON

[rmrbytes]

I came across this library while searching for just this functionality. Thanks for sharing it.

I was wondering whether it would be possible to kind of reverse engineer and determine the parameter values given a resultant json.

Let me give an example to clarify what I am seeking:

Suppose the template is defined as

const template = parse("{
    title: 'Fixed Title",
   {foo:baz}
 }");

And passing a foo value generates the json

console.log(template({foo: 'baz'}) // prints {title:'Fixed Title', foo: 'baz'}

But is there a way to get the params given the resultant json. I am using a function called extract as an example to explain what will be useful

console.log(template.extract({title: 'Fixed Title', foo: 'baq'}) // prints {foo: 'baq'} 

Thanks

[curran]

Interesting idea! It might be possible.

I would welcome a PR if you'd like to attempt a solution.

Do you have any initial thoughts on how a solution might be implemented?

It reminds me of this JSON diff library I've worked with https://github.com/kbadk/json0-ot-diff

[rmrbytes]

Thanks @curran for your response. I am doing something like this.

const extractJson = (templateJson, resultJson) => {
    // get template
    const template = parse(templateJson)
    // get params
    const params = template.parameters
    // construct extract json
    let _ejson = {}
    // loop through params
    for (let i = 0; i < params.length; i++) {
        const _keyname = params[i].key
        // findKey of _keyname
        const _arr = findKey(_new, _keyname)
        // check not null
        if (_arr.length > 0) {
            _ejson[_keyname] = _arr[0]
        }
        else {
            _ejson[_keyname] = null
        }
        return _ejson
  }
}

// find key function
const findKey = (obj, keyname) => {
    let result = []
    const mergeArray = (s1, s2) => result = [...s1, ...s2];
    if (Array.isArray(obj)) {
        obj.forEach(o => {
            mergeArray(result, findKey(o, keyname))
        })
    } else {
        if (typeof obj === 'object') {
            Object.keys(obj).forEach(k => {
                if (k === keyname) {
                    result.push(obj[k])
                }
                if (obj[k] !== undefined && obj[k] !== null)
                    mergeArray(result, findKey(obj[k], keyname))
            })
        }
    }
    return result
}

[rmrbytes]

or if you already have the template

const extractJson = (template, resultJson) => {
    // get params
    const params = template.parameters
    // construct extract json
    let _ejson = {}
    // loop through params
    for (let i = 0; i < params.length; i++) {
        const _keyname = params[i].key
        // findKey of _keyname
        const _arr = findKey(_new, _keyname)
        // check not null
        if (_arr.length > 0) {
            _ejson[_keyname] = _arr[0]
        }
        else {
            _ejson[_keyname] = null
        }
        return _ejson
  }
}

[curran]

Awesome! Happy to accept a PR if you add tests and docs.

[rmrbytes]

Hello @curran :

While I did send you PR, I realise that it has a limitation. In the above method, I am assuming that the context object (the input json) key is the same name as the parameter. I did not account for cases where that may not be true. In which case, the PR sent will fail. Obviously, this is an after thought and hence I do not have any test case that checks for this too.

I will think up of some other compare logic to determine locating the param in the context object