feat: backport Key.asKey (#42)

Backports #41 to previous release.

packages/interface-datastore/src/key.js

@@ -111,6 +111,23 @@ class Key {
     return new Key(nanoid().replace(/-/g, ''))
   }
 
+  /**
+   * @param {*} other
+   */
+  static asKey (other) {
+    if (other instanceof Uint8Array || typeof other === 'string') {
+      // we can create a key from this
+      return new Key(other)
+    }
+
+    if (other.uint8Array) {
+      // this is an older version or may have crossed the esm/cjs boundary
+      return new Key(other.uint8Array())
+    }
+
+    return null
+  }
+
   /**
    * Cleanup the current key
    *

packages/interface-datastore/test/key.spec.js

@@ -3,6 +3,7 @@
 
 const { expect } = require('aegir/utils/chai')
 const Key = require('../src').Key
+const { fromString: uint8ArrayFromString } = require('uint8arrays/from-string')
 
 const pathSep = '/'
 
@@ -206,4 +207,37 @@ describe('Key', () => {
     // should be a view on the original buffer
     expect(buf.buffer).to.equal(arrWithSlashes.buffer)
   })
+
+  it('should turn a string into a key', () => {
+    const str = '/foo/bar'
+    const key = Key.asKey(str)
+
+    expect(`${key}`).to.equal(str)
+  })
+
+  it('should turn a key into a key', () => {
+    const str = '/foo/bar'
+    const key = Key.asKey(new Key(str))
+
+    expect(`${key}`).to.equal(str)
+  })
+
+  it('should turn a uint8array into a key', () => {
+    const str = '/foo/bar'
+    const key = Key.asKey(uint8ArrayFromString(str))
+
+    expect(`${key}`).to.equal(str)
+  })
+
+  it('should not turn a falsy value into a key', () => {
+    const key = Key.asKey(false)
+
+    expect(key).to.be.null()
+  })
+
+  it('should not turn an invalid value into a key', () => {
+    expect(Key.asKey({})).to.be.null()
+    expect(Key.asKey(5)).to.be.null()
+    expect(Key.asKey(() => {})).to.be.null()
+  })
 })