fix: fixes #230 by returning a through stream that emits the error instead of throwing it

Author: achingbrain

package.json

@@ -51,7 +51,7 @@
     "pull-stream-to-stream": "^1.3.4",
     "pull-zip": "^2.0.1",
     "rimraf": "^2.6.2",
-    "sinon": "^6.1.5"
+    "sinon": "^7.1.0"
   },
   "dependencies": {
     "async": "^2.6.1",

src/chunker/rabin.js

@@ -1,17 +1,24 @@
 'use strict'
 
 const toPull = require('stream-to-pull-stream')
+const through = require('pull-through')
 
 let createRabin
 
 module.exports = (options) => {
   if (!createRabin) {
     try {
       createRabin = require('rabin')
-    } catch (error) {
-      error.message = `Rabin chunker not supported, it may have failed to install - ${error.message}`
 
-      throw error
+      if (typeof createRabin !== 'function') {
+        throw new Error('createRabin was not a function')
+      }
+    } catch (err) {
+      const error = new Error(`Rabin chunker not available, it may have failed to install or not be supported on this platform`)
+
+      return through(function () {
+        this.emit('error', error)
+      })
     }
   }
 

test/browser.js

@@ -41,6 +41,7 @@ describe('IPFS data importing tests on the Browser', function () {
 
   // Chunkers
   require('./chunker-fixed-size')
+  require('./chunker-rabin-browser')
 
   // Graph Builders
   require('./builder')(repo)

test/chunker-rabin-browser.js

@@ -0,0 +1,31 @@
+/* eslint-env mocha */
+'use strict'
+
+const chunker = require('./../src/chunker/rabin')
+const chai = require('chai')
+chai.use(require('dirty-chai'))
+const expect = chai.expect
+const pull = require('pull-stream')
+
+describe('chunker: rabin browser', function () {
+  it('returns an error', (done) => {
+    const b1 = Buffer.alloc(2 * 256)
+    const b2 = Buffer.alloc(1 * 256)
+    const b3 = Buffer.alloc(5 * 256)
+
+    b1.fill('a')
+    b2.fill('b')
+    b3.fill('c')
+
+    pull(
+      pull.values([b1, b2, b3]),
+      chunker({minChunkSize: 48, avgChunkSize: 96, maxChunkSize: 192}),
+      pull.collect((err) => {
+        expect(err).to.exist()
+        expect(err.message).to.include('Rabin chunker not available')
+
+        done()
+      })
+    )
+  })
+})