feat: more encoding, errors, spec tests

src/base.js

@@ -16,7 +16,7 @@ class Base {
   decode (string) {
     for (const char of string) {
       if (this.alphabet && this.alphabet.indexOf(char) < 0) {
-        throw new Error(`invalid ${this.name} character '${char}' in '${string}'`)
+        throw new Error(`invalid character '${char}' in '${string}'`)
       }
     }
     return this.engine.decode(string)

src/index.js

@@ -55,6 +55,12 @@ function decode (data) {
   if (Buffer.isBuffer(data)) {
     data = data.toString()
   }
+  const prefix = data[0]
+
+  // Make all encodings case-insensitive expect the ones that include upper and lower chars in the alphabet
+  if (!['z', 'Z', 'm', 'M', 'u', 'U', '\x00'].includes(prefix)) {
+    data = data.toLocaleLowerCase()
+  }
   const enc = encoding(data[0])
   return Buffer.from(enc.decode(data.substring(1)))
 }

test/spec-test1.spec.js

@@ -67,7 +67,7 @@ describe('spec test1', () => {
         const nonEncodedBuf = Buffer.from(base.code + '^!@$%!#$%@#y')
         expect(() => {
           multibase.decode(nonEncodedBuf)
-        }).to.throw(Error, `invalid ${name} character '^' in '^!@$%!#$%@#y'`)
+        }).to.throw(Error, 'invalid character \'^\' in \'^!@$%!#$%@#y\'')
       })
     })
   }

test/spec-test6.spec.js

@@ -19,8 +19,7 @@ const encoded = [
   ['base36upper', 'KfUVrSIVVnFRbJWAJo']
 ]
 
-// we dont need to actually test these because we check the chars against the alphabet
-describe.skip('spec test6', () => {
+describe('spec test6', () => {
   for (const e of encoded) {
     const name = e[0]
     const output = e[1]