task4--改变函数参数

length/src/index.js

+import * as Constants from './constants'
 export class Length {
   value
   unit
-  static FOOT = 'foot'
-  static YARD = 'yard'
-  static INCH = 'inch'
 
   constructor(val, uint) {
     this.value = val
@@ -19,26 +17,26 @@ export class Length {
   }
   parseTo(unitNode) {
     let unitLength = this
-    if (this.unit === Length.YARD ) {
-      if (unitNode === Length.FOOT) {
+    if (this.unit === Constants.Constants.YARD) {
+      if (unitNode === Constants.Constants.FOOT) {
         unitLength = new Length(this.value * 3, unitNode)
-      } else if (unitNode === Length.INCH) {
+      } else if (unitNode === Constants.Constants.INCH) {
         unitLength = new Length(this.value * 36, unitNode)
       }
     }
 
-    if (this.unit === Length.INCH) {
-      if (unitNode === Length.YARD) {
+    if (this.unit === Constants.Constants.INCH) {
+      if (unitNode === Constants.Constants.YARD) {
         unitLength = new Length(this.value / 36, unitNode)
-      } else if (unitNode === Length.FOOT) {
+      } else if (unitNode === Constants.Constants.FOOT) {
         unitLength = new Length(this.value / 12, unitNode)
       }
     }
 
-    if (this.unit === Length.FOOT) {
-      if (unitNode === Length.YARD) {
+    if (this.unit === Constants.Constants.FOOT) {
+      if (unitNode === Constants.Constants.YARD) {
         unitLength = new Length(this.value / 3, unitNode)
-      } else if (unitNode === Length.INCH) {
+      } else if (unitNode === Constants.Constants.INCH) {
         unitLength = new Length(this.value * 12, unitNode)
       }
     }

length/src/index.test.js

 import { Length } from './index'
+import {Constants} from './constants'
 
 describe('Length', () => {
   it("should 1 'foot' equals 1 'foot'", () => {
-    const length = new Length(1, Length.FOOT)
+    const length = new Length(1, Constants.FOOT)
 
     expect(length.getVal()).toEqual(1)
-    expect(length.getUint()).toEqual(Length.FOOT)
+    expect(length.getUint()).toEqual(Constants.FOOT)
   })
 
   it("should 1 'foot' equals 12 inches", () => {
-    const result = new Length(1, Length.FOOT).parseTo(Length.INCH)
+    const result = new Length(1, Constants.FOOT).parseTo(Constants.INCH)
 
     expect(result.getVal()).toEqual(12)
-    expect(result.getUint()).toEqual(Length.INCH)
+    expect(result.getUint()).toEqual(Constants.INCH)
   })
 
-  it("should 3 feet equals 1 Length.YARD", () => {
-    const result = new Length(3, Length.FOOT).parseTo(Length.YARD)
+  it("should 3 feet equals 1 yard", () => {
+    const result = new Length(3, Constants.FOOT).parseTo(Constants.YARD)
 
     expect(result.getVal()).toEqual(1)
-    expect(result.getUint()).toEqual(Length.YARD)
+    expect(result.getUint()).toEqual(Constants.YARD)
   })
 
-  it("should 1 Length.YARD equals 3 feet", () => {
-    const result = new Length(1, Length.YARD).parseTo(Length.FOOT)
+  it("should 1 Constants.YARD equals 3 feet", () => {
+    const result = new Length(1, Constants.YARD).parseTo(Constants.FOOT)
 
     expect(result.getVal()).toEqual(3)
-    expect(result.getUint()).toEqual(Length.FOOT)
+    expect(result.getUint()).toEqual(Constants.FOOT)
   })
 
-  it("should 1 Length.YARD equals 36 inches", () => {
-    const result = new Length(1, Length.YARD).parseTo(Length.INCH)
+  it("should 1 Constants.YARD equals 36 inches", () => {
+    const result = new Length(1, Constants.YARD).parseTo(Constants.INCH)
 
     expect(result.getVal()).toEqual(36)
-    expect(result.getUint()).toEqual(Length.INCH)
+    expect(result.getUint()).toEqual(Constants.INCH)
   })
 
-  it("should 1 Length.YARD equals 1 Length.YARD", () => {
-    const result = new Length(1, Length.YARD).parseTo(Length.YARD)
+  it("should 1 Constants.YARD equals 1 Constants.YARD", () => {
+    const result = new Length(1, Constants.YARD).parseTo(Constants.YARD)
 
     expect(result.getVal()).toEqual(1)
-    expect(result.getUint()).toEqual(Length.YARD)
+    expect(result.getUint()).toEqual(Constants.YARD)
   })
 
   it("should 12 inches equals 1 'foot'", () => {
-    const result = new Length(12, Length.INCH).parseTo(Length.FOOT)
+    const result = new Length(12, Constants.INCH).parseTo(Constants.FOOT)
 
     expect(result.getVal()).toEqual(1)
-    expect(result.getUint()).toEqual(Length.FOOT)
+    expect(result.getUint()).toEqual(Constants.FOOT)
   })
 
   it("should 36 inches equals 1 yard", () => {
-    const result = new Length(36, Length.INCH).parseTo(Length.YARD)
+    const result = new Length(36, Constants.INCH).parseTo(Constants.YARD)
 
     expect(result.getVal()).toEqual(1)
-    expect(result.getUint()).toEqual(Length.YARD)
+    expect(result.getUint()).toEqual(Constants.YARD)
   })
 
   it("should 1 inch equals 1 inch", () => {
-    const result = new Length(1, Length.INCH).parseTo(Length.INCH)
+    const result = new Length(1, Constants.INCH).parseTo(Constants.INCH)
 
     expect(result.getVal()).toEqual(1)
-    expect(result.getUint()).toEqual(Length.INCH)
+    expect(result.getUint()).toEqual(Constants.INCH)
   })
 })