From bc146aaefbdab07b7775a280b01c49a21f5c56e5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=AD=99=E9=A2=A2?= <sunhao@bestminr.com>
Date: Thu, 27 Dec 2018 17:30:08 +0800
Subject: [PATCH] =?UTF-8?q?feat:=20=E6=B7=BB=E5=8A=A0=20get=20utils?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 @types/index.d.ts |  7 ++++++
 src/utils/get.ts  | 55 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 62 insertions(+)
 create mode 100644 src/utils/get.ts

diff --git a/@types/index.d.ts b/@types/index.d.ts
index 279c787..4c79723 100644
--- a/@types/index.d.ts
+++ b/@types/index.d.ts
@@ -411,5 +411,12 @@ declare namespace build {
        */
       unpdate: (middlewares: any[]) => void
     }
+
+    namespace Get {
+      interface BaseGetOptions {
+        strict?: boolean
+        defaultValue?: any
+      }
+    }
   }
 }
diff --git a/src/utils/get.ts b/src/utils/get.ts
new file mode 100644
index 0000000..3f9f304
--- /dev/null
+++ b/src/utils/get.ts
@@ -0,0 +1,55 @@
+
+import { utils } from "@types";
+type BaseGetOptions = utils.Get.BaseGetOptions
+
+/**
+ * 安全获取对象的值 - 不报错
+ * * 可能为 undefined
+ * @param obj 读取对象
+ * @param args 读取路径
+ */
+export function getValue<T extends object> (obj: T): T
+export function getValue<T extends object, K1 extends keyof T> (obj: T, k1: K1): T[K1]
+export function getValue<T extends object, K1 extends keyof T, K2 extends keyof T[K1]> (obj: T, k1: K1, k2: K2): T[K1][K2]
+export function getValue<T extends object, K1 extends keyof T, K2 extends keyof T[K1], K3 extends keyof T[K1][K2]> (obj: T, k1: K1, k2: K2, k3: K3): T[K1][K2][K3]
+export function getValue(obj: any, ...args: string[]) {
+  return obj == null ? undefined : baseGet(obj, args)
+}
+
+/**
+ * 安全获取对象的值 - 会报错
+ * * 必须使用 try - catch
+ * @param obj 读取对象
+ * @param options 配置参数
+ * @param args 读取路径
+ */
+export function getInsureValue<T extends object>(obj: T, options: BaseGetOptions): T
+export function getInsureValue<T extends object, K1 extends keyof T>(obj: T, options: BaseGetOptions, k1: K1): T[K1]
+export function getInsureValue<T extends object, K1 extends keyof T, K2 extends keyof T[K1]>(obj: T, options: BaseGetOptions, k1: K1, k2: K2): T[K1][K2]
+export function getInsureValue<T extends object, K1 extends keyof T, K2 extends keyof T[K1], K3 extends keyof T[K1][K2]>(obj: T, options: BaseGetOptions, k1: K1, k2: K2, k3: K3): T[K1][K2][K3]
+export function getInsureValue(obj: any, options: BaseGetOptions = {}, ...args: string[]) {
+  Object.assign(options, { strict: true })
+  return obj == null ? undefined : baseGet(obj, args, options)
+}
+
+
+function baseGet(object: any, path: string[], { strict, defaultValue }: BaseGetOptions = {}) {
+  let index = 0
+  const length = path.length
+  while (object != null && index < length) {
+    object = object[path[index++]]
+  }
+  if (index === length) {
+    return object
+  } else {
+    if (strict) {
+      if (!defaultValue) {
+        throw new Error(
+          `[getValue] Uncaught TypeError: Object.${path.join('.')} Cannot read property '${path[index]}' of undefined.`,
+        )
+      } return defaultValue
+    } else {
+      return undefined
+    }
+  }
+}
\ No newline at end of file