refactor(base64): mutualized base64 functions into global utilities

src/utils/base64.test.ts

@@ -0,0 +1,69 @@
+import { describe, expect, it } from 'vitest';
+import { base64ToText, isValidBase64, removePotentialDataAndMimePrefix, textToBase64 } from './base64';
+
+describe('base64 utils', () => {
+  describe('textToBase64', () => {
+    it('should convert string into base64', () => {
+      expect(textToBase64('')).to.eql('');
+      expect(textToBase64('a')).to.eql('YQ==');
+      expect(textToBase64('lorem ipsum')).to.eql('bG9yZW0gaXBzdW0=');
+      expect(textToBase64('-1')).to.eql('LTE=');
+    });
+  });
+
+  describe('base64ToText', () => {
+    it('should convert base64 into text', () => {
+      expect(base64ToText('')).to.eql('');
+      expect(base64ToText('YQ==')).to.eql('a');
+      expect(base64ToText('bG9yZW0gaXBzdW0=')).to.eql('lorem ipsum');
+      expect(base64ToText('data:text/plain;base64,bG9yZW0gaXBzdW0=')).to.eql('lorem ipsum');
+      expect(base64ToText('LTE=')).to.eql('-1');
+    });
+
+    it('should throw for incorrect base64 string', () => {
+      expect(() => base64ToText('a')).to.throw('Incorrect base64 string');
+      expect(() => base64ToText(' ')).to.throw('Incorrect base64 string');
+      expect(() => base64ToText('é')).to.throw('Incorrect base64 string');
+      // missing final '='
+      expect(() => base64ToText('bG9yZW0gaXBzdW0')).to.throw('Incorrect base64 string');
+    });
+  });
+
+  describe('isValidBase64', () => {
+    it('should return true for correct base64 string', () => {
+      expect(isValidBase64('')).to.eql(true);
+      expect(isValidBase64('bG9yZW0gaXBzdW0=')).to.eql(true);
+      expect(isValidBase64('LTE=')).to.eql(true);
+      expect(isValidBase64('YQ==')).to.eql(true);
+      expect(isValidBase64('data:text/plain;base64,YQ==')).to.eql(true);
+    });
+
+    it('should return false for incorrect base64 string', () => {
+      expect(isValidBase64('a')).to.eql(false);
+      expect(isValidBase64(' ')).to.eql(false);
+      expect(isValidBase64('é')).to.eql(false);
+      expect(isValidBase64('data:text/plain;notbase64,YQ==')).to.eql(false);
+      // missing final '='
+      expect(isValidBase64('bG9yZW0gaXBzdW0')).to.eql(false);
+    });
+
+    it('should return false for untrimmed correct base64 string', () => {
+      expect(isValidBase64('bG9yZW0gaXBzdW0= ')).to.eql(false);
+      expect(isValidBase64(' LTE=')).to.eql(false);
+      expect(isValidBase64(' YQ== ')).to.eql(false);
+    });
+  });
+
+  describe('removePotentialDataAndMimePrefix', () => {
+    it('should remove data prefix of string', () => {
+      expect(removePotentialDataAndMimePrefix('')).to.eql('');
+      expect(removePotentialDataAndMimePrefix('lorem ipsum')).to.eql('lorem ipsum');
+      expect(removePotentialDataAndMimePrefix('bG9yZW0gaXBzdW0=')).to.eql('bG9yZW0gaXBzdW0=');
+      expect(removePotentialDataAndMimePrefix('data:image/jpeg;base64,lorem')).to.eql('lorem');
+      expect(removePotentialDataAndMimePrefix('data:image/jpeg;notbase64,lorem')).to.eql(
+        'data:image/jpeg;notbase64,lorem',
+      );
+      expect(removePotentialDataAndMimePrefix('data:unknownmime;base64,lorem')).to.eql('lorem');
+    });
+  });
+});

src/utils/base64.ts

@@ -0,0 +1,33 @@
+export { textToBase64, base64ToText, isValidBase64, removePotentialDataAndMimePrefix };
+
+function textToBase64(str: string) {
+  return window.btoa(str);
+}
+
+function base64ToText(str: string) {
+  if (!isValidBase64(str)) {
+    throw new Error('Incorrect base64 string');
+  }
+
+  const cleanStr = removePotentialDataAndMimePrefix(str);
+
+  try {
+    return window.atob(cleanStr);
+  } catch (_) {
+    throw new Error('Incorrect base64 string');
+  }
+}
+
+function removePotentialDataAndMimePrefix(str: string) {
+  return str.replace(/^data:.*?;base64,/, '');
+}
+
+function isValidBase64(str: string) {
+  const cleanStr = removePotentialDataAndMimePrefix(str);
+
+  try {
+    return window.btoa(window.atob(cleanStr)) === cleanStr;
+  } catch (err) {
+    return false;
+  }
+}

src/utils/defaults.test.ts

@@ -0,0 +1,16 @@
+import { describe, expect, it } from 'vitest';
+import { withDefaultOnError } from './defaults';
+
+describe('defaults util', () => {
+  describe('withDefaultOnError', () => {
+    it('should return the callback or the default one if the callback throws', () => {
+      expect(withDefaultOnError(() => 'original', 'default')).to.eql('original');
+    });
+
+    expect(
+      withDefaultOnError(() => {
+        throw '';
+      }, 'default'),
+    ).to.eql('default');
+  });
+});

src/utils/defaults.ts

@@ -0,0 +1,9 @@
+export { withDefaultOnError };
+
+function withDefaultOnError<A, B>(cb: () => A, defaultValue: B): A | B {
+  try {
+    return cb();
+  } catch (_) {
+    return defaultValue;
+  }
+}