feat: add a function to verify and return Abilities.

packages/capabilities/src/types.ts

@@ -633,9 +633,9 @@ export type PlanGetFailure = PlanNotFound
 // Top
 export type Top = InferInvokedCapability<typeof top>
 
-export type Abilities = TupleToUnion<AbilitiesArray>
+export type W3UpAbility = TupleToUnion<W3UpAbilityArray>
 
-export type AbilitiesArray = [
+export type W3UpAbilityArray = [
   Top['can'],
   ProviderAdd['can'],
   Space['can'],
@@ -677,3 +677,13 @@ export type AbilitiesArray = [
   Usage['can'],
   UsageReport['can']
 ]
+
+/**
+ * @deprecated use Ability
+ */
+export type Abilities = W3UpAbility
+
+/**
+ * @deprecated use AbilityArray
+ */
+export type AbilitiesArray = W3UpAbilityArray

packages/w3up-client/src/ability.js

@@ -0,0 +1,32 @@
+import { abilitiesAsStrings } from '@web3-storage/capabilities'
+
+const setOfAbilities = new Set(abilitiesAsStrings)
+
+/**
+ * Verify and return Abilities.
+ *
+ * Given a list of strings representing capability names (Abilities),
+ * verify that all the strings are valid Abilities and return Abilities[].
+ *
+ * Abilities[] is still just a list of strings, but this helps us play
+ * nice with Typescript.
+ *
+ * @param {string[]} abilities
+ * @returns {import('@web3-storage/capabilities/types').W3UpAbility[]}
+ */
+export function asAbilities(abilities) {
+  for (const ability of abilities) {
+    if (
+      !setOfAbilities.has(
+        /** @type {import('@web3-storage/capabilities/types').W3UpAbility} */ (
+          ability
+        )
+      )
+    ) {
+      throw new Error(`${ability} is not a supported capability`)
+    }
+  }
+  return /** @type {import('@web3-storage/capabilities/types').W3UpAbility[]} */ (
+    abilities
+  )
+}

packages/w3up-client/src/index.js

@@ -11,6 +11,7 @@ import { generate } from '@ucanto/principal/rsa'
 import { Client } from './client.js'
 export * as Result from './result.js'
 export * as Account from './account.js'
+export * from './ability.js'
 
 /**
  * Create a new w3up client.

packages/w3up-client/test/ability.test.js

@@ -0,0 +1,21 @@
+import assert from 'assert'
+import { asAbilities } from '../src/ability.js'
+
+describe('abilities', () => {
+  it('should return the passed argument if all abilities are valid', async () => {
+    const abilities = ['store/add', 'upload/add']
+    assert.equal(asAbilities(abilities), abilities)
+  })
+
+  it('should throw an error if one of the abilities is not supported', async () => {
+    assert.throws(
+      () => {
+        asAbilities(['foo/bar'])
+      },
+      {
+        name: 'Error',
+        message: 'foo/bar is not a supported capability',
+      }
+    )
+  })
+})