feat: add randomString, jsonp

src/index.ts

@@ -33,12 +33,14 @@ export { default as isPromise } from './isPromise'
 export { default as isRegExp } from './isRegExp'
 export { default as isString } from './isString'
 export { default as isUndefined } from './isUndefined'
+export { default as jsonp } from './jsonp'
 export { default as mapValues } from './mapValues'
 export { default as noop } from './noop'
 export { default as omit } from './omit'
 export { default as parseCssValue } from './parseCssValue'
 export { default as pick } from './pick'
 export { default as preventEventDefault } from './preventEventDefault'
+export { default as randomString } from './randomString'
 export { default as reduce } from './reduce'
 export { default as repeat } from './repeat'
 export { default as shuffle } from './shuffle'

src/jsonp.ts

@@ -0,0 +1,48 @@
+import inBrowser from './inBrowser'
+import isObject from './isObject'
+import noop from './noop'
+import randomString from './randomString'
+import reduce from './reduce'
+
+const objectToQueryString = (obj: object): string => {
+  return reduce(
+    obj,
+    (str, value, key) => str += `&${encodeURIComponent(key)}=${encodeURIComponent(value)}`,
+    ''
+  )
+}
+
+export default function jsonp(url: string, data?: string | object, callbackParameter = 'callback'): Promise<any> {
+  return new Promise(
+    inBrowser()
+      ? (resolve, reject) => {
+          let script: HTMLScriptElement
+
+          const callbackFunctionName = `jsonp${randomString()}`
+          const queryString = `${
+            isObject(data) ? objectToQueryString(data) : (data != null ? String(data) : '')
+          }&${
+            encodeURIComponent(callbackParameter)
+          }=${
+            encodeURIComponent(callbackFunctionName)
+          }`
+          const requestUrl = url + (url.indexOf('?') > -1 ? '&' : '?') + queryString;
+
+          (window as any)[callbackFunctionName] = (response: any) => {
+            resolve(response)
+            try {
+              delete (window as any)[callbackFunctionName]
+              document.body.removeChild(script)
+            } catch (err) {}
+          }
+
+          script = document.createElement('script')
+          script.src = requestUrl
+          script.async = true
+          script.onerror = reject
+
+          document.body.appendChild(script)
+        }
+      : noop
+    )
+}

src/randomString.ts

@@ -0,0 +1,8 @@
+/**
+ * 返回一个随机的字符串。
+ *
+ * @returns 随机的字符串
+ */
+export default function randomString(): string {
+  return Math.random().toString(36).substr(2)
+}

test/index.test.ts

@@ -829,3 +829,27 @@ describe('storage', () => {
     expect(vtils.storage.get('hello')).toBeNull()
   })
 })
+
+describe('randomString', () => {
+  test('ok', () => {
+    const r: string[] = []
+    for (let i = 0; i < 10000; i++) {
+      const str = vtils.randomString()
+      expect(r.indexOf(str) === -1).toBeTruthy()
+      r.push(str)
+    }
+  })
+})
+
+// describe('jsonp', () => {
+//   test('ok', done => {
+//     vtils.jsonp('https://jsonplaceholder.typicode.com/todos/1')
+//       .then(obj => {
+//         expect(obj).toContainEqual({
+//           userId: 1,
+//           id: 1
+//         })
+//         done()
+//       })
+//   })
+// })