py-liant/pyliant.js at master · tripsolutions/py-liant · GitHub

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function pyliant_decode(o) {
    var id_map = {}
    var incomplete_refs = {}
    function object_xform(o) {
        if ('_ref' in o) {
            if (o._ref in id_map)
                return id_map[o._ref]
            // add to incomplete refs and id map
            incomplete_refs[o._ref] = o
            id_map[o._ref] = o
            delete o._ref
            // will be filled in later
            return o
        }

        if ('_id' in o) {
            if (o._id in incomplete_refs) {
                var ref = incomplete_refs[o._id]
                // is being filled in, no longer incomplete
                delete incomplete_refs[o._id]
                delete o._id
                for (var key in o) {
                    if (o[key] instanceof Array)
                        ref[key] = array_xform(o[key])
                    else if (o[key] instanceof Object)
                        ref[key] = object_xform(o[key])
                    else
                        ref[key] = o[key]
                }
                return ref
            }
            id_map[o._id] = o
            delete o._id
        }

        for (var key in o) {
            if (o[key] instanceof Array)
                o[key] = array_xform(o[key])
            else if (o[key] instanceof Object)
                o[key] = object_xform(o[key])
        }
        return o
    }

    function array_xform(arr) {
        var ret = []
        for (var i in arr) {
            if (arr[i] instanceof Array)
                ret.push(array_xform(arr[i]))
            else if (arr[i] instanceof Object)
                ret.push(object_xform(arr[i]))
            else
                ret.push(arr[i])
        }
        return ret
    }

    return object_xform(o)
}

function pyliant_encode(o) {
    var id_set = new WeakSet()
    var id_map = new WeakMap()
    var current = 1
    function object_xform(o) {
        if (id_map.has(o)) {
            var ref = id_map.get(o)
            if (!('_id' in ref))
                ref._id = current++
            return { _ref: ref._id }
        }
        var ref = {}
        id_map.set(o, ref)
        for (var key in o) {
            if (o[key] instanceof Array)
                ref[key] = array_xform(o[key])
            else if (o[key] instanceof Object)
                ref[key] = object_xform(o[key])
            else
                ref[key] = o[key]
        }
        return ref
    }

    // arrays should never be referenced multiple times
    // this is reserved for object only
    function array_xform(arr) {
        var ret = []
        for (var i in arr) {
            if (arr[i] instanceof Array)
                ret.push(array_xform(arr[i]))
            else if (arr[i] instanceof Object)
                ret.push(object_xform(arr[i]))
            else
                ret.push(arr[i])
        }
        return ret
    }

    return object_xform(o)
}