[improvement] rename packages dir to src (#3659)

src/utils/format/number.ts

@@ -0,0 +1,3 @@
+export function range(num: number, min: number, max: number): number {
+  return Math.min(Math.max(num, min), max);
+}

src/utils/format/string.ts

@@ -0,0 +1,9 @@
+const camelizeRE = /-(\w)/g;
+
+export function camelize(str: string): string {
+  return str.replace(camelizeRE, (_, c) => c.toUpperCase());
+}
+
+export function padZero(num: number | string): string {
+  return (num < 10 ? '0' : '') + num;
+}

src/utils/format/unit.ts

@@ -0,0 +1,11 @@
+import { isDef } from '..';
+import { isNumber } from '../validate/number';
+
+export function suffixPx(value?: string | number): string | undefined {
+  if (!isDef(value)) {
+    return undefined;
+  }
+
+  value = String(value);
+  return isNumber(value) ? `${value}px` : value;
+}