typed-path

Typed Path

Problem

Types are lost when string paths are used in typescript.
I.e., _.get, _.map, _.set, R.pluck from libraries like lodash, ramda.
It makes those methods dangerous in case of refactoring, the same as JavaScript.

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Solution

Errors

With typed-path, typescript can check paths and warns you about errors.

Path access methods

Default

.$path

@m-abboud
Also, you can get access to the path string using $path special field.

Like this:

    console.log(tp<TestType>().a.b.c.d.$path); // this will output "a.b.c.d"

.$raw

@dcbrwn
If you need a raw path, which is of type string[] - you can get it using $raw special field.
Deprecated, since it transforms symbols and numbers to strings, which might be not an expected behavior (the method name is "raw"). Please use .$rawPath

    console.log(tp<TestType>().a.b.c.d.$raw); // this will output ["a", "b", "c", "d"]

.$rawPath

If you need a raw path, which is of type (string | number | Symbol)[] - you can get it using $rawPath special field.

    console.log(tp<TestType>().a.b[5].c.d.$rawPath); // this will output ["a", "b", 5, "c", "d"]

The $rawPath is something that you might want to use with the following methods from Ramda, to add type safety on the path:

• R.assocPath,
• R.dissocPath,
• R.hasPath,
• R.path,
• R.pathEq,
• R.pathOr,
• R.paths,
• R.lensPath

Example: https://codesandbox.io/s/typed-path-ramda-assoc-path-x3qby?file=/src/index.ts

Additional handlers

@nick-lvov-dev

You can extend path handlers functionality using additional handlers:

const testAdditionalHandlers = {
    $url: (path: string[]) => path.join('/')
}

console.log(tp<TestType, typeof testAdditionalHandlers>(testAdditionalHandlers).a.b.c.$url); // this will output "a/b/c"

The additional handlers are also chainable:

const testAdditionalHandlers = {
    $abs: (path: string[]) => typedPath<TestType, typeof testAdditionalHandlers>(testAdditionalHandlers, ['', ...path]),
    $url: (path: string[]) => path.join('/')
}

console.log(tp<TestType, typeof testAdditionalHandlers>(testAdditionalHandlers).a.b.c.$abs.$url); // this will output "/a/b/c"

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Suggestions

Also, typed-path allows typescript to suggest field names for you.

License

Copyright (c) 2020 Oleksandr Beshchuk <[e-mail]>
Licensed under the Apache License.