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# YUI Library Examples: DataSchema Utility: DataSchema.JSON

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## DataSchema Utility: DataSchema.JSON

DataSchema.JSON normalizes arbitrary JSON data against a given schema into an object with known properties.

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#### Basic example

###### Data

    {
        "total":10,
        "results":[
            {"n":1, "fname":"George", "lname":"Washington"},
            {"n":2, "fname":"John", "lname":"Adams"},
            {"n":3, "fname":"Thomas", "lname":"Jefferson"},
            {"n":4, "fname":"James", "lname":"Madison"},
            {"n":5, "fname":"James", "lname":"Monroe"},
            {"n":6, "fname":"John", "mname":"Quincy", "lname":"Adams"},
            {"n":7, "fname":"Andrew", "lname":"Jackson"},
            {"n":8, "fname":"Martin", "lname":"Van Buren"},
            {"n":9, "fname":"William", "mname":"Henry", "lname":"Harrison"},
            {"n":10, "fname":"John", "lname":"Tyler"}
        ]
    }

###### Schema

    {
        metaFields: {total:"total"},
        resultListLocator: "results",
        resultFields: [{key:"n"}, {key:"fname"}, {key:"lname"}]
    }

###### Normalized data

#### Complex example

###### Data

    {
        "profile":{
            "current":160,
            "target":150
        },
        "reference": [
            {
                "category":"exercise",
                "type":"expenditure",
                "activities":[
                    {"name":"biking", "calories":550},
                    {"name":"golf", "calories":1000},
                    {"name":"running", "calories":650},
                    {"name":"swimming", "calories":650},
                    {"name":"walking", "calories":225}
                ]
            },
            {
                "category":"nutrition",
                "type":"intake",
                "fruit":[
                    {"name":"apple", "calories":70},
                    {"name":"banana", "calories":70},
                    {"name":"orange", "calories":90},
                ],
                "vegetables":[
                    {"name":"baked potato", "calories":150},
                    {"name":"broccoli", "calories":50},
                    {"name":"green beans", "calories":30}
                ]
            }
        ],
        "program": [
            {
                "category":"exercise",
                "schedule":[
                    {"day":"sunday", "activity":"swimming"},
                    {"day":"monday", "activity":"running"},
                    {"day":"tuesday", "activity":"biking"},
                    {"day":"wednesday", "activity":"running"},
                    {"day":"thursday", "activity":"swimming"},
                    {"day":"friday", "activity":"running"},
                    {"day":"saturday", "activity":"golf"}
                ]
            },
            {
                "category":"diet",
                "schedule":[
                ]
            }
        ]
    }

###### Schema

    {
        metaFields: {current:"profile.current", target:"profile.target",
            reference:"reference[0].activities"},
        resultListLocator: "program[0].schedule",
        resultFields: [{key:"day"}, {key:"activity"}]
    }

###### Normalized data

In order to use DataSchema.JSON, input data must be a JavaScript object.

YUI().use("dataschema-json", function(Y) { var data_in = { total:10, results:[ {n:1, fname:"George", lname:"Washington"}, {n:2, fname:"John", lname:"Adams"}, {n:3, fname:"Thomas", lname:"Jefferson"}, {n:4, fname:"James", lname:"Madison"}, {n:5, fname:"James", lname:"Monroe"}, {n:6, fname:"John", mname:"Quincy", lname:"Adams"}, {n:7, fname:"Andrew", lname:"Jackson"}, {n:8, fname:"Martin", lname:"Van Buren"}, {n:9, fname:"William", mName:"Henry", lname:"Harrison"}, {n:10, fname:"John", lname:"Tyler"} ] }, schema = { metaFields: {total:"total"}, resultListLocator: "results", resultFields: [{key:"n"}, {key:"fname"}, {key:"lname"}] // Or simply: ["n", "fname", "lname"] }, data_out = Y.DataSchema.JSON.apply(schema, data_in)); alert(data_out); });

The data itself can get fairly complex, with deeply nested arrays and objects. In your schema, you can use dot notation and the array-index syntax to define these locations. When necessary, you can also use object-bracket notation to define locations that might otherwise be invalid with dot notation.

YUI().use("dataschema-json", function(Y) { var data_in = { "profile":{ "current":160, "target":150 }, "reference": [ { "category":"exercise", "type":"expenditure", "activities":[ {"name":"biking", "calories":550}, {"name":"golf", "calories":1000}, {"name":"running", "calories":650}, {"name":"swimming", "calories":650}, {"name":"walking", "calories":225} ] }, { "category":"nutrition", "type":"intake", "fruit":[ {"name":"apple", "calories":70}, {"name":"banana", "calories":70}, {"name":"orange", "calories":90}, ], "vegetables":[ {"name":"baked potato", "calories":150}, {"name":"broccoli", "calories":50}, {"name":"green beans", "calories":30} ] } ], "program": [ { "category":"exercise", "weekly schedule":[ {"day":"sunday", "activity":"swimming"}, {"day":"monday", "activity":"running"}, {"day":"tuesday", "activity":"biking"}, {"day":"wednesday", "activity":"running"}, {"day":"thursday", "activity":"swimming"}, {"day":"friday", "activity":"running"}, {"day":"saturday", "activity":"golf"} ] }, { "category":"diet", "schedule":[ ] } ] }, schema = { metaFields: {current:"profile.current", target:"profile.target", reference:"reference[0].activities"}, resultListLocator: "program[0]['weekly schedule']", resultFields: [{key:"day"}, {key:"activity"}] // Or simply: ["day", "activity"] }, data_out = Y.DataSchema.Array.apply(schema, data_in)); alert(data_out); });

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