Allow null input on Text values (#2682)

* Allow `null` input on `Text` values

* Update test

* Add to decode section

* Revert result

CHANGELOG.md

@@ -1,5 +1,11 @@
 # CHANGELOG
 
+## 2.1.2-x
+
+Changes:
+
+- Allow `null` input on `Text` values
+
 ## 2.1.1 Oct 5, 2020
 
 Upgrade priority: Low.

packages/types/src/primitive/Text.spec.ts

@@ -10,7 +10,7 @@ describe('Text', (): void => {
   const registry = new TypeRegistry();
 
   describe('decode', (): void => {
-    const testDecode = (type: string, input: string | Uint8Array | { toString: () => string }, expected: string, toFn: 'toString' | 'toHex' = 'toString'): void =>
+    const testDecode = (type: string, input: null | string | Uint8Array | { toString: () => string }, expected: string, toFn: 'toString' | 'toHex' = 'toString'): void =>
       it(`can decode from ${type}`, (): void => {
         expect(new Text(registry, input)[toFn]()).toBe(expected);
       });
@@ -21,6 +21,7 @@ describe('Text', (): void => {
     testDecode('Raw', new Raw(registry, Uint8Array.from([102, 111, 111])), 'foo'); // no length
     testDecode('object with `toString()`', { toString (): string { return 'foo'; } }, 'foo');
     testDecode('hex input value', new Text(registry, '0x12345678'), '0x12345678', 'toHex');
+    testDecode('null', null, '');
   });
 
   describe('encode', (): void => {

packages/types/src/primitive/Text.ts

@@ -12,7 +12,7 @@ import Raw from '../codec/Raw';
 const MAX_LENGTH = 128 * 1024;
 
 /** @internal */
-function decodeText (value: Text | string | AnyU8a | { toString: () => string }): string {
+function decodeText (value?: null | Text | string | AnyU8a | { toString: () => string }): string {
   if (isHex(value)) {
     return u8aToString(hexToU8a(value.toString()));
   } else if (value instanceof Uint8Array) {
@@ -35,7 +35,7 @@ function decodeText (value: Text | string | AnyU8a | { toString: () => string })
     return u8aToString(value.subarray(offset, total));
   }
 
-  return value.toString();
+  return value ? value.toString() : '';
 }
 
 /**
@@ -53,7 +53,7 @@ export default class Text extends String implements Codec {
 
   #override: string | null = null;
 
-  constructor (registry: Registry, value: Text | string | AnyU8a | { toString: () => string } = '') {
+  constructor (registry: Registry, value?: null | Text | string | AnyU8a | { toString: () => string }) {
     super(decodeText(value));
 
     this.registry = registry;