ast-get-values-by-key^4.0.1

Quick Take

import { strict as assert } from "assert";
import { getByKey } from "ast-get-values-by-key";

// GETTER
// ======

// returns "object-path" notation paths where arrays use dots:
assert.deepEqual(
  getByKey(
    {
      parsed: [
        {
          tag: "html",
        },
      ],
    },
    "tag" // value to search for
  ),
  [{ val: "html", path: "parsed.0.tag" }]
);

// SETTER
// ======

assert.deepEqual(
  getByKey(
    {
      parsed: [
        {
          tag: "html",
        },
      ],
      foo: {
        tag: null,
      },
      bar: {
        tag: null,
      },
    },
    "tag", // value to search for
    [123, 456] // pot of values to pick from (one result not enough)
  ),
  {
    parsed: [
      {
        tag: 123,
      },
    ],
    foo: {
      tag: 456,
    },
    bar: {
      tag: null, // value pot was depleted and there was nothing left to put here
    },
  }
);

Examples

• program example: Replace all null's in keys amount with zero, but only under orders
• program example: Using wildcards (matcher api)

Purpose

There are many ways to work with AST's — huge nested trees of objects and arrays. This program is one of the possible ways.

Two arguments trigger the GET mode — it returns an array of objects with value-path findings.

If you map that into desired values array and rerun it, this time putting desired values as a third input argument, you get the SET mode.

API

getByKey(
  input, 
  whatToFind, 
  [replacement]
)

• If two arguments are given, it's getter. You'll receive an array of zero or more plain objects with keys: val and path, where path follows object-path  notation.

• If three arguments are given, it's setter. You'll receive a copy of original input, changed accordingly.

This library does not mutate any input arguments.

Getter

To search ("get") put two input arguments, for example:

const findings = getByKey(source, ["*cles"]);

See the examples section. Paths are using object-path  notation. Where vanilla JS path would use brackets to address array elements: nested[0].cutticles, object-path notation uses dots still: nested.0.cutticles. The rest is the same.

Setter

To set values, put three input arguments, for example:

const result = getByKey(source, ["*cles"], ["a", "b", "c"]);

The third argument, ["a", "b", "c"] above, is the pot of values to put for each finding. The idea is that you'd use a getter first, prepare the amended values array, then feed it again into this program and change the input (AST or whatever plain object or array or whatever).

Changelog

See it in the monorepo , on GitHub.

Contributing

To report bugs or request features or assistance, raise an issue on GitHub .

Any code contributions welcome! All Pull Requests will be dealt promptly.

Licence

MIT 

Copyright © 2010–2021 Roy Revelt and other contributors