chore: add calNum

Author: Simon he

src/calNum.ts

@@ -0,0 +1,59 @@
+export const calNum = {
+  add(...args: (number | string)[]): number {
+    return args.reduce((total, num) => accAdd(+total, +num)) as number;
+  },
+  sub(...args: (number | string)[]): number {
+    return args.reduce((total, num) => accAdd(+total, -num)) as number;
+  },
+  mul(...args: (number | string)[]): number {
+    return args.reduce((total, num) => accMul(+total, +num)) as number;
+  },
+  div(...args: (number | string)[]): number {
+    return args.reduce((total, num) => accDiv(+total, +num)) as number;
+  },
+}
+
+
+function accAdd(arg1: number, arg2: number): number {
+  let r1, r2, m;
+  try {
+    r1 = arg1.toString().split('.')[1].length;
+  } catch (e) {
+    r1 = 0;
+  }
+  try {
+    r2 = arg2.toString().split('.')[1].length;
+  } catch (e) {
+    r2 = 0;
+  }
+  m = Math.pow(10, Math.max(r1, r2));
+  return (arg1 * m + arg2 * m) / m;
+};
+
+function accMul(arg1: number, arg2: number): number {
+  let m = 0;
+  let s1 = arg1.toString();
+  let s2 = arg2.toString();
+  try {
+    m += s1.split('.')[1].length;
+  } catch (e) { }
+  try {
+    m += s2.split('.')[1].length;
+  } catch (e) { }
+  return Number(s1.replace('.', '')) * Number(s2.replace('.', '')) / Math.pow(10, m);
+};
+
+function accDiv(arg1: number, arg2: number): number {
+  let t1 = 0;
+  let t2 = 0;
+  let r1; let r2;
+  try {
+    t1 = arg1.toString().split('.')[1].length;
+  } catch (e) { }
+  try {
+    t2 = arg2.toString().split('.')[1].length;
+  } catch (e) { }
+  r1 = Number(arg1.toString().replace('.', ''));
+  r2 = Number(arg2.toString().replace('.', ''));
+  return (r1 / r2) * Math.pow(10, t2 - t1);
+};