feat: Add WriterFunctions.assertion.

dsherret · May 15, 2019 · 37c875e · 37c875e
1 parent cfce40b
commit 37c875e
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Showing 3 changed files with 23 additions and 0 deletions.
diff --git a/lib/ts-morph.d.ts b/lib/ts-morph.d.ts
@@ -1928,6 +1928,10 @@ export declare class WriterFunctions {
      * Gets a writer function for writing an intersection type.
      */
     static intersectionType(firstType: WriterFunctionOrValue, secondType: WriterFunctionOrValue, ...additionalTypes: WriterFunctionOrValue[]): (writer: CodeBlockWriter) => void;
+    /**
+     * Gets a writer function for writing a type assertion (ex. `type as assertionType`).
+     */
+    static assertion(type: WriterFunctionOrValue, assertionType: WriterFunctionOrValue): (writer: CodeBlockWriter) => void;
 }
 
 export declare type WriterFunctionOrValue = string | number | WriterFunction;

diff --git a/src/structurePrinters/WriterFunctions.ts b/src/structurePrinters/WriterFunctions.ts
@@ -75,6 +75,15 @@ export class WriterFunctions {
     static intersectionType(firstType: WriterFunctionOrValue, secondType: WriterFunctionOrValue, ...additionalTypes: WriterFunctionOrValue[]) {
         return getWriteFunctionForUnionOrIntersectionType("&", [firstType, secondType, ...additionalTypes]);
     }
+
+    /** Gets a writer function for writing a type assertion (ex. `type as assertionType`). */
+    static assertion(type: WriterFunctionOrValue, assertionType: WriterFunctionOrValue) {
+        return (writer: CodeBlockWriter) => {
+            writeValue(writer, type);
+            writer.spaceIfLastNot().write("as ");
+            writeValue(writer, assertionType);
+        };
+    }
 }
 
 function getWriteFunctionForUnionOrIntersectionType(separator: "|" | "&", args: WriterFunctionOrValue[]) {

diff --git a/src/tests/structurePrinters/writerFunctionsTests.ts b/src/tests/structurePrinters/writerFunctionsTests.ts
@@ -128,4 +128,14 @@ describe(nameof<WriterFunctions>(), () => {
             doWriterTest((writer, { intersectionType }) => intersectionType("C", "A", w => w.write("5"), 7)(writer), "C & A & 5 & 7");
         });
     });
+
+    describe(nameof(WriterFunctions.assertion), () => {
+        it("should write when specifying writer functions", () => {
+            doWriterTest((writer, { assertion }) => assertion(w => w.write("a"), w => w.write("b"))(writer), "a as b");
+        });
+
+        it("should write when specifying strings", () => {
+            doWriterTest((writer, { assertion }) => assertion("a", "b")(writer), "a as b");
+        });
+    });
 });