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Make URLPath.fromString infallible
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samhh committed May 1, 2024
1 parent 6dd2f51 commit 75123e2
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2 changes: 2 additions & 0 deletions CHANGELOG.md
Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,8 @@ This project adheres to semantic versioning.

## _Unreleased_

- Improve `fromString` in `URLPath` to infallibly parse all strings.
- Remove `fromStringO` from `URLPath`.
- Fix `toURL`/`toURLO` in `URLPath` failing to prioritise the retention of the provided base URL.

## 0.19.1 (2024-04-08)
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44 changes: 6 additions & 38 deletions docs/modules/URLPath.ts.md
Original file line number Diff line number Diff line change
Expand Up @@ -26,7 +26,6 @@ Added in v0.17.0
- [clone](#clone)
- [fromPathname](#frompathname)
- [fromString](#fromstring)
- [fromStringO](#fromstringo)
- [fromURL](#fromurl)
- [getHash](#gethash)
- [getParams](#getparams)
Expand Down Expand Up @@ -158,17 +157,17 @@ Added in v0.17.0

## fromString

Build a `URLPath` from a string containing any parts. For an infallible
alternative taking only a pathname, consider `fromPathname`.
Build a `URLPath` from a relative or absolute string containing any parts.
Consider also `fromPathname` where only a pathname needs to be parsed.

**Signature**

```ts
export declare const fromString: <E>(f: (e: TypeError) => E) => (x: string) => Either<E, URLPath>
export declare const fromString: (x: string) => URLPath
```
```hs
fromString :: (TypeError -> e) -> string -> Either e URLPath
fromString :: string -> URLPath
```

**Example**
Expand All @@ -178,41 +177,10 @@ import { pipe, constant } from 'fp-ts/function'
import * as E from 'fp-ts/Either'
import { fromString, fromPathname, setHash } from 'fp-ts-std/URLPath'

const f = fromString(constant('oops'))

const expected = pipe('/foo', fromPathname, setHash('bar'))

assert.deepStrictEqual(f('/foo#bar'), E.right(expected))
assert.deepStrictEqual(f('//'), E.left('oops'))
```

Added in v0.17.0

## fromStringO

Build a `URLPath` from a string containing any parts, forgoing the error.

**Signature**

```ts
export declare const fromStringO: (x: string) => Option<URLPath>
```
```hs
fromStringO :: string -> Option URLPath
```

**Example**

```ts
import { pipe } from 'fp-ts/function'
import * as O from 'fp-ts/Option'
import { fromStringO, fromPathname, setHash } from 'fp-ts-std/URLPath'

const expected = pipe('/foo', fromPathname, setHash('bar'))

assert.deepStrictEqual(fromStringO('/foo#bar'), O.some(expected))
assert.deepStrictEqual(fromStringO('//'), O.none)
assert.deepStrictEqual(fromString('/foo#bar'), expected)
assert.deepStrictEqual(fromString('https://samhh.com/foo#bar'), expected)
```

Added in v0.17.0
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67 changes: 26 additions & 41 deletions src/URLPath.ts
Original file line number Diff line number Diff line change
Expand Up @@ -14,6 +14,7 @@ import type { Endomorphism } from "fp-ts/Endomorphism"
import * as Eq_ from "fp-ts/Eq"
import type { Option } from "fp-ts/Option"
import * as O from "fp-ts/Option"
import type { Predicate } from "fp-ts/Predicate"
import type { Refinement } from "fp-ts/Refinement"
import { flow, identity, pipe } from "fp-ts/function"
import type { Newtype } from "newtype-ts"
Expand All @@ -39,14 +40,21 @@ export type URLPath = Newtype<URLPathSymbol, URL>

const phonyBase = new globalThis.URL("https://urlpath.fp-ts-std.samhh.com")

const ensureBase: Endomorphism<URL> = x =>
const ensurePhonyBase: Endomorphism<URL> = x =>
pipe(phonyBase, URL.clone, b => {
b.pathname = x.pathname
b.search = Params.toString(x.searchParams)
b.hash = x.hash
return b
})

const hasPhonyBase: Predicate<URL> = x => x.origin === phonyBase.origin

const assertPhonyBase: Endomorphism<URL> = x => {
if (!hasPhonyBase(x)) throw new Error("Invalid phony base")
return x
}

/**
* Check if a foreign value is a `URLPath`.
*
Expand Down Expand Up @@ -101,7 +109,7 @@ export const clone: Endomorphism<URLPath> = over(URL.clone)
* @since 0.17.0
*/
export const fromURL = (x: URL): URLPath =>
pipe(new globalThis.URL(x.href, phonyBase), ensureBase, pack<URLPath>)
pipe(new globalThis.URL(x.href, phonyBase), ensurePhonyBase, pack<URLPath>)

/**
* Convert a `URLPath` to a `URL` with the provided `baseUrl`.
Expand Down Expand Up @@ -168,57 +176,34 @@ export const toURLO = (baseUrl: string): ((x: URLPath) => Option<URL>) =>
flow(toURL(identity)(baseUrl), O.fromEither)

/**
* Build a `URLPath` from a string containing any parts. For an infallible
* alternative taking only a pathname, consider `fromPathname`.
* Build a `URLPath` from a relative or absolute string containing any parts.
* Consider also `fromPathname` where only a pathname needs to be parsed.
*
* @example
* import { pipe, constant } from 'fp-ts/function';
* import * as E from 'fp-ts/Either';
* import { fromString, fromPathname, setHash } from 'fp-ts-std/URLPath'
*
* const f = fromString(constant('oops'))
*
* const expected = pipe('/foo', fromPathname, setHash('bar'))
*
* assert.deepStrictEqual(f('/foo#bar'), E.right(expected))
* assert.deepStrictEqual(f('//'), E.left('oops'))
* assert.deepStrictEqual(fromString('/foo#bar'), expected)
* assert.deepStrictEqual(fromString('https://samhh.com/foo#bar'), expected)
*
* @category 3 Functions
* @since 0.17.0
*/
export const fromString =
<E>(f: (e: TypeError) => E) =>
(x: string): Either<E, URLPath> =>
pipe(
// It should only throw some sort of `TypeError`:
// https://developer.mozilla.org/en-US/docs/Web/API/URL/URL
E.tryCatch(
() => ensureBase(new globalThis.URL(x, phonyBase)),
e => f(e as TypeError),
),
E.map(pack<URLPath>),
)

/**
* Build a `URLPath` from a string containing any parts, forgoing the error.
*
* @example
* import { pipe } from 'fp-ts/function';
* import * as O from 'fp-ts/Option';
* import { fromStringO, fromPathname, setHash } from 'fp-ts-std/URLPath'
*
* const expected = pipe('/foo', fromPathname, setHash('bar'))
*
* assert.deepStrictEqual(fromStringO('/foo#bar'), O.some(expected))
* assert.deepStrictEqual(fromStringO('//'), O.none)
*
* @category 3 Functions
* @since 0.17.0
*/
export const fromStringO: (x: string) => Option<URLPath> = flow(
fromString(identity),
O.fromEither,
)
export const fromString = (x: string): URLPath =>
pipe(
E.tryCatch(
() => assertPhonyBase(new globalThis.URL(x, phonyBase)),
identity,
),
E.alt(() =>
E.tryCatch(() => new globalThis.URL(`${phonyBase.origin}${x}`), identity),
),
E.getOrElse(() => new globalThis.URL(`${phonyBase.origin}/${x}`)),
pack<URLPath>,
)

/**
* Build a `URLPath` from a path. Characters such as `?` will be encoded.
Expand Down
83 changes: 36 additions & 47 deletions test/URLPath.test.ts
Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,7 @@ import fc from "fast-check"
import * as laws from "fp-ts-laws"
import * as E from "fp-ts/Either"
import * as O from "fp-ts/Option"
import { apply, constant, flip, flow, identity, pipe } from "fp-ts/function"
import { apply, flip, flow, identity, pipe } from "fp-ts/function"
import {
unsafeUnwrapLeft,
unsafeUnwrap as unsafeUnwrapRight,
Expand All @@ -22,7 +22,6 @@ import {
clone,
fromPathname,
fromString,
fromStringO,
fromURL,
getHash,
getParams,
Expand Down Expand Up @@ -50,8 +49,7 @@ const phonyBase = "https://urlpath.fp-ts-std.samhh.com"
const validBase = "https://samhh.com"
const invalidBase = "samhh.com"

const validPath = "/f/g.h?i=j&k=l&i=m#n"
const invalidPath = "//"
const examplePath = "/f/g.h?i=j&k=l&i=m#n"

describe("URLPath", () => {
describe("isURLPath", () => {
Expand All @@ -61,22 +59,22 @@ describe("URLPath", () => {
expect(f("foo")).toBe(false)
expect(f(new URL(validBase))).toBe(false)
expect(f(new URL(phonyBase))).toBe(true)
expect(f(new URL(phonyBase + validPath))).toBe(true)
expect(f(new URL(phonyBase + examplePath))).toBe(true)
})
})

describe("clone", () => {
const f = clone

it("clones to an identical URLPath", () => {
const x = fromPathname(validPath)
const x = fromPathname(examplePath)

expect(f(x)).toEqual(x)
expect(toString(f(x))).toBe(toString(x))
})

it("clones without references", () => {
const x = fromPathname(validPath)
const x = fromPathname(examplePath)
;(x as unknown as URL).pathname = "/foo"
;(x as unknown as URL).search = "?foo=food&bar=bard&foo=fool"
const y = f(x)
Expand All @@ -99,7 +97,7 @@ describe("URLPath", () => {
const f = fromURL

it("retains the path, params, and hash", () => {
const x = new URL(validBase + validPath)
const x = new URL(validBase + examplePath)
const y = pipe(x, f, unpack)

expect(y.pathname).toEqual(x.pathname)
Expand Down Expand Up @@ -179,60 +177,51 @@ describe("URLPath", () => {
})

describe("fromString", () => {
const f = fromString(constant("e"))
const f = fromString
const g = flow(f, u => (u as unknown as URL).href)

it("succeeds for valid paths", () => {
expect(f("")).toEqual(E.right(new URL("", phonyBase)))
expect(f(validPath)).toEqual(E.right(new URL(validPath, phonyBase)))
})
it("parses all parts", () => {
const [x, y, z] = Fn.fork([getPathname, getParams, getHash])(
f("/foo?bar=yes#baz"),
)

it("passes a TypeError to the callback on failure", () => {
const e = pipe(invalidPath, fromString(identity), unsafeUnwrapLeft)
expect(x).toBe("/foo")
expect(y).toEqual(new URLSearchParams({ bar: "yes" }))
expect(z).toBe("#baz")
})

// This doesn't work. I suspect a tooling bug. Sanity check in the REPL.
// expect(e).toBeInstanceOf(TypeError)
it("parses typical paths", () => {
expect(g("/")).toBe(`${phonyBase}/`)
expect(g("/foo.bar")).toBe(`${phonyBase}/foo.bar`)
expect(g(examplePath)).toBe(`${phonyBase}${examplePath}`)
})

expect(e.name).toBe("TypeError")
it("parses atypical paths", () => {
expect(g("")).toBe(`${phonyBase}/`)
expect(g("//")).toBe(`${phonyBase}//`)
expect(g("//x")).toBe(`${phonyBase}//x`)
expect(g("///")).toBe(`${phonyBase}///`)
expect(g(":123")).toBe(`${phonyBase}/:123`)
expect(g(".net")).toBe(`${phonyBase}/.net`)
})

it("accepts all valid paths", () => {
it("is infallible", () => {
fc.assert(
fc.property(fc.webPath(), x =>
expect(f(x)).toEqual(E.right(new URL(x, phonyBase))),
),
fc.property(fc.oneof(fc.string(), fc.webPath()), x => {
f(x)
}),
)
})

it("parses but does not retain origins", () => {
const g = flow(
fromString(identity),
E.map(x => (x as unknown as URL).href),
)

expect(g("//x")).toEqual(E.right(`${phonyBase}/`))
expect(g("https://samhh.com/foo")).toEqual(E.right(`${phonyBase}/foo`))

it("always keeps phony base", () => {
fc.assert(
fc.property(fc.string().map(f).filter(E.isRight), ({ right: x }) =>
expect((x as unknown as URL).origin).toBe(phonyBase),
fc.property(fc.oneof(fc.string(), fc.webPath()), x =>
expect((f(x) as unknown as URL).origin).toBe(phonyBase),
),
)
})
})

describe("fromStringO", () => {
const f = fromStringO

it("succeeds for valid paths", () => {
expect(f("")).toEqual(O.some(new URL("", phonyBase)))
expect(f(validPath)).toEqual(O.some(new URL(validPath, phonyBase)))
})

it("fails for invalid paths", () => {
expect(f(invalidPath)).toEqual(O.none)
})
})

describe("toString", () => {
const f = toString

Expand Down Expand Up @@ -420,7 +409,7 @@ describe("URLPath", () => {

describe("Eq", () => {
const f = Eq.equals
const g = flow(fromStringO, unsafeUnwrapO)
const g = fromString

it("works", () => {
const x = "/foo.bar#baz"
Expand Down

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