Stefan Hacker
99 lines
1.8 KiB
Markdown
99 lines
1.8 KiB
Markdown
# JSON Pointer - `json-pointer`
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Fast implementation of [JSON Pointer (RFC 6901)][json-pointer]
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specification in TypeScript.
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[json-pointer]: https://tools.ietf.org/html/rfc6901
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## Usage
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Can find a value in a JSON object using three methods: (1) JSON Pointer string,
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(2) array of steps, or (3) a pre-compiled function.
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## Examples
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Find the value in a JSON document at some specific location.
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### Find by JSON Pointer string
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```js
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import { findByPointer } from '@jsonjoy.com/json-pointer';
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const doc = {
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foo: {
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bar: 123,
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},
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};
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const res = findByPointer(doc, '/foo/bar');
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```
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### Find by path array
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Alternatively, you can specify an array of steps, such as `['foo', 'bar']`. Or,
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use the `parseJsonPointer` function to convert a JSON Pointer string to an array.
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```js
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import { find, parseJsonPointer } from '@jsonjoy.com/json-pointer';
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const doc = {
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foo: {
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bar: 123,
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},
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};
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const path = parseJsonPointer('/foo/bar');
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const ref = find(doc, path);
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console.log(ref);
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// { val: 123, obj: { bar: 123 }, key: 'bar' }
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```
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### Pre-compiled function
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If you know the path in advance, you can compile a function that will find the
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value at that location, it will work few times faster than the previous methods.
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```js
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import { $$find } from '@jsonjoy.com/json-pointer/lib/codegen';
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const doc = {
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foo: {
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bar: 123,
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},
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};
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const finder = $$find(['foo', 'bar']);
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const res = finder(doc);
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```
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## Low-level API
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Convert JSON Pointer to path array and back.
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```js
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import { parseJsonPointer } from '@jsonjoy.com/json-pointer';
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console.log(parseJsonPointer('/f~0o~1o/bar/1/baz'));
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// [ 'f~o/o', 'bar', '1', 'baz' ]
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console.log(formatJsonPointer(['f~o/o', 'bar', '1', 'baz']));
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// /f~0o~1o/bar/1/baz
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```
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Decode and encode a single step of JSON Pointer.
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```js
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console.log(unescapeComponent('~0~1'));
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// ~/
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console.log(escapeComponent('~/'));
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// ~0~1
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```
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