Package Exports

mappingutils
mappingutils/dist/index.js

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (mappingutils) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

mappingutils

Transform input objects with ease.

MapObj Example

import { mapObj } from "mappingutils";

let source = `
{
    "store": {
        "book": [
            {
                "category": "reference",
                "author": "Nigel Rees",
                "title": "Sayings of the Century",
                "price": 8.95
            },
            {
                "category": "fiction",
                "author": "Evelyn Waugh",
                "title": "Sword of Honour",
                "price": 12.99
            },
            {
                "category": "fiction",
                "author": "Herman Melville",
                "title": "Moby Dick",
                "isbn": "0-553-21311-3",
                "price": 8.99
            },
            {
                "category": "fiction",
                "author": "J. R. R. Tolkien",
                "title": "The Lord of the Rings",
                "isbn": "0-395-19395-8",
                "price": 22.99
            }
        ],
        "bicycle": {
            "color": "red",
            "price": 19.95
        }
    },
    "expensive": 10
}
`;

let transformation = [
    {
        from: 'store.book[?(@.category=="fiction")].category',
        to: "category",
    },
    {
        from: 'store.book[?(@.category=="fiction")].author',
        to: "author",
    },
    {
        from: 'store.book[?(@.category=="fiction")].title',
        to: "book.title",
    },
    {
        from: 'store.book[?(@.category=="fiction")].price',
        to: "book.price",
    },
];

let outputArr = mapObj(JSON.parse(source), transformation);
console.log(JSON.stringify(outputArr, null, 2));

// [
//   {
//     "category": "fiction",
//     "author": "Evelyn Waugh",
//     "book": {
//       "title": "Sword of Honour",
//       "price": 12.99
//     }
//   },
//   {
//     "category": "fiction",
//     "author": "Herman Melville",
//     "book": {
//       "title": "Moby Dick",
//       "price": 8.99
//     }
//   },
//   {
//     "category": "fiction",
//     "author": "J. R. R. Tolkien",
//     "book": {
//       "title": "The Lord of the Rings",
//       "price": 22.99
//     }
//   }
// ]

It uses JSONPath syntax for selecting the values from the input and a similar syntax for the output.

Another example where grouping by books for the fiction category using the same input as before.

import { mapObj, mergeObjArr } from "mappingutils";

let transformation = [
    {
        from: 'store.book[?(@.category=="fiction")].category',
        to: "category",
    },
    {
        from: 'store.book[?(@.category=="fiction")].title',
        to: "books[].name",
    },
    {
        from: 'store.book[?(@.category=="fiction")].author',
        to: "books[].author",
    },
];

let outputArr = mapObj(JSON.parse(source), transformation);
let merged = mergeObjArr(outputArr, "books[*]");
console.log(JSON.stringify(merged, null, 2));

// {
//   "category": "fiction",
//   "books": [
//     {
//       "name": "Sword of Honour",
//       "author": "Evelyn Waugh"
//     },
//     {
//       "name": "Moby Dick",
//       "author": "Herman Melville"
//     },
//     {
//       "name": "The Lord of the Rings",
//       "author": "J. R. R. Tolkien"
//     }
//   ]
// }

Methods

addProp(obj, key, value)

Add a key property to the object obj with the value value. Returns a deep copy of the object with the new property added.

mergeObjArr(objArr, prop)

Merge the prop array values of the object objArr. Returns a deep copy of the first object in the array, with the prop array values concatenated.

mapObj(source, mappings)

Transforms an input object source given the provided array of mappings mappings. Returns an array of objects resulting from transforming the input object.

mapObjArr(source, mappings)

Transforms an input array of objects source given the provided array of mappings mappings. Returns an array of objects resulting from transforming the input objects.

License

MIT