feat: 新增方法 padZero

src/index.js

@@ -44,6 +44,7 @@ export { default as setDataURLPrefix } from './setDataURLPrefix';
 export { default as normalizeString } from './normalizeString';
 export { default as safeDate } from './safeDate';
 export { default as formatMobile } from './formatMobile';
+export { default as padZero } from './padZero';
 
 /**
  * 数学计算，修正浮点数计算问题

src/padZero.js

@@ -0,0 +1,39 @@
+import normalizeString from './normalizeString';
+
+/**
+ * 前置补零
+ *
+ * @static
+ * @alias module:Processor.padZero
+ * @since 4.7.0
+ * @param {string|number} value 要处理的值
+ * @param {number} [size=2] 指定字符串长度
+ * @returns {string} 用零填充数字到给定长度的字符串
+ * @example
+ * padZero(5); // '05'
+ * padZero('5'); // '05'
+ *
+ * padZero(12); // '12'
+ * padZero('12'); // '12'
+ *
+ * padZero(688); // '688'
+ * padZero('688'); // '688'
+ *
+ * padZero(688, 5); // '00688'
+ * padZero('688', 5); // '00688'
+ */
+function padZero(value, size = 2) {
+  const str = normalizeString(value);
+  const len = str.length;
+
+  if (typeof size !== 'number' || size < 0) {
+    size = 0;
+  }
+
+  if (len < size) {
+    return '0'.repeat(size - len) + str;
+  }
+  return str;
+}
+
+export default padZero;

test/processor/padZero.test.js

@@ -0,0 +1,63 @@
+import { padZero } from '../../src';
+
+describe('padZero', () => {
+  it('should be defined', () => {
+    expect(padZero).toBeDefined();
+  });
+
+  it('correct', () => {
+    expect(padZero(0)).toBe('00');
+    expect(padZero(0.2)).toBe('0.2');
+    expect(padZero(1)).toBe('01');
+    expect(padZero(9)).toBe('09');
+    expect(padZero(10)).toBe('10');
+    expect(padZero(28)).toBe('28');
+    expect(padZero(688)).toBe('688');
+
+    expect(padZero(0, 3)).toBe('000');
+    expect(padZero(0.2, 3)).toBe('0.2');
+    expect(padZero(1, 3)).toBe('001');
+    expect(padZero(9, 3)).toBe('009');
+    expect(padZero(10, 3)).toBe('010');
+    expect(padZero(28, 3)).toBe('028');
+    expect(padZero(688, 3)).toBe('688');
+
+    expect(padZero(0, 5)).toBe('00000');
+    expect(padZero(0.2, 5)).toBe('000.2');
+    expect(padZero(1, 5)).toBe('00001');
+    expect(padZero(9, 5)).toBe('00009');
+    expect(padZero(10, 5)).toBe('00010');
+    expect(padZero(28, 5)).toBe('00028');
+    expect(padZero(688, 5)).toBe('00688');
+  });
+
+  it('incorrect', () => {
+    expect(padZero()).toBe('00');
+    expect(padZero(undefined)).toBe('00');
+    expect(padZero(void 0)).toBe('00');
+    expect(padZero(null)).toBe('00');
+
+    expect(padZero(undefined, 0)).toBe('');
+    expect(padZero(undefined, 5)).toBe('00000');
+    expect(padZero(null, 0)).toBe('');
+    expect(padZero(null, 5)).toBe('00000');
+
+    expect(padZero(undefined, '')).toBe('');
+    expect(padZero(undefined, '12')).toBe('');
+    expect(padZero(undefined, null)).toBe('');
+    expect(padZero(undefined)).toBe('00');
+
+    expect(padZero(false, '')).toBe('false');
+    expect(padZero(false, '12')).toBe('false');
+    expect(padZero(false, null)).toBe('false');
+    expect(padZero(false, void 0)).toBe('false');
+
+    expect(padZero(true, '')).toBe('true');
+    expect(padZero(true, '12')).toBe('true');
+    expect(padZero(true, null)).toBe('true');
+    expect(padZero(true, void 0)).toBe('true');
+
+    expect(padZero(true, 5)).toBe('0true');
+    expect(padZero(true, true)).toBe('true');
+  });
+});