@@ -0,0 +1,37 @@
+// 字面量 = 变量只能是你写死的那个值 必须是一个精确地值
+let a: 10;
+// a =20;
+// 逻辑运算符 | (联合类型)
+let b: 'man' | 'woman';
+b = 'man';
+b = 'woman'
+let c1: number = 10;
+let c2: string = '10';
+let c3: null = null;
+let c4: undefined = undefined;
+let c5: boolean = true;
+let c6: symbol = Symbol("xxx");
+let c7: bigint = BigInt(5637742873827823784);
+// null undefined区别
+// b = 12;
+// 任意类型 隐性
+// let d: any;
+let d;
+// d = 1;
+d = '12';
+// d = Symbol(1);
+// d = null;
+// 未知类型 安全的any 显性
+let e: unknown;
+// let e;
+// e = 1;
+e = '12';
+// e = Symbol(1);
+// e = null;
+// any unknown 区别
+// any可以给任意变量赋值
+// unknown不能直接赋值
+let f:string;
+// f = d;
+// f = e;
+export { }
zheng