feat(math): 添加getNumberFromUnit方法，获取单位前的数字

mathUtil/src/index.ts

@@ -1,6 +1,6 @@
 /* eslint-disable no-restricted-globals */
 // 判断传入的是否是数字或者可转为数字的字符串
-export const isNumber = (value: string | number) => {
+export const isNumber = (value: string | number): boolean => {
   return /^(-|\+)?\d+(\.\d+)?$/.test(value as string);
 };
 
@@ -23,3 +23,13 @@ export const roundToString = (
   const value = roundForObj(obj, decimal);
   return value.toFixed(decimal);
 };
+
+// 取单位前的数字，并转换成整数
+export const getNumberFromUnit = (unit: string): number => {
+  const reg = new RegExp('^[0-9]+');
+  if (unit && reg.test(unit)) {
+    const arr: any = unit.match(reg);
+    return parseInt(arr[0], 10);
+  }
+  return 1;
+};