Recognize promise then call with rejection handler as valid floating …

…promise handling (#3048)
palantir · Jul 25, 2017 · 3369ff8 · 3369ff8
1 parent 9afcf17
commit 3369ff8
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Showing 2 changed files with 12 additions and 2 deletions.
diff --git a/src/rules/noFloatingPromisesRule.ts b/src/rules/noFloatingPromisesRule.ts
@@ -59,7 +59,9 @@ function walk(ctx: Lint.WalkContext<string[]>, tc: ts.TypeChecker) {
     return ts.forEachChild(ctx.sourceFile, function cb(node): void {
         if (isExpressionStatement(node)) {
             const { expression } = node;
-            if (isCallExpression(expression) && !isPromiseCatchCall(expression)) {
+            if (isCallExpression(expression) &&
+                !isPromiseCatchCall(expression) &&
+                !isPromiseThenCallWithRejectionHandler(expression)) {
                 const { symbol } = tc.getTypeAtLocation(expression);
                 if (symbol !== undefined && ctx.options.indexOf(symbol.name) !== -1) {
                     ctx.addFailureAtNode(expression, Rule.FAILURE_STRING);
@@ -73,3 +75,9 @@ function walk(ctx: Lint.WalkContext<string[]>, tc: ts.TypeChecker) {
 function isPromiseCatchCall(expression: ts.CallExpression): boolean {
     return isPropertyAccessExpression(expression.expression) && expression.expression.name.text === "catch";
 }
+
+function isPromiseThenCallWithRejectionHandler(expression: ts.CallExpression): boolean {
+    return isPropertyAccessExpression(expression.expression) &&
+        expression.expression.name.text === "then" &&
+        expression.arguments.length >= 2;
+}
diff --git a/test/rules/no-floating-promises/promises/test.ts.lint b/test/rules/no-floating-promises/promises/test.ts.lint
@@ -156,4 +156,6 @@ switch(foo) {
 
 returnsPromiseFunction().catch(e => { console.error(e.stack); });
 
-[0]: Promises must be handled appropriately
+returnsPromiseFunction().then(() => {}, e => { console.error(e.stack); });
+
+[0]: Promises must be handled appropriately