1 files changed, 15 insertions, 2 deletions
diff --git a/typescript.html.markdown b/typescript.html.markdown
index 55d8cefe..cf2111d5 100644
--- a/typescript.html.markdown
+++ b/typescript.html.markdown
@@ -224,6 +224,19 @@ moreNumbers.push(5); // Error, no push method (because it mutates array)
 moreNumbers.length = 3; // Error, length is read-only
 numbers = moreNumbers; // Error, mutating methods are missing
 
+// Tagged Union Types for modelling state that can be in one of many shapes
+type State = 
+  | { type: "loading" }
+  | { type: "success", value: number }
+  | { type: "error", message: string };
+
+declare const state: State;
+if (state.type === "success") {
+  console.log(state.value);
+} else if (state.type === "error") {
+  console.error(state.message);
+}
+
 // Iterators and Generators
 
 // for..of statement
@@ -235,13 +248,13 @@ for (const val of arrayOfAnyType) {
 
 let list = [4, 5, 6];
 for (const i of list) {
-   console.log(i); // "4", "5", "6"
+   console.log(i); // 4, 5, 6
 }
 
 // for..in statement
 // iterate over the list of keys on the object being iterated
 for (const i in list) {
-   console.log(i); // "0", "1", "2",
+   console.log(i); // 0, 1, 2
 }