Detection of boolean return values. (08b86793) · Commits · extjs / jsduck

lib/jsduck/function_ast.rb

+37 −0

Original line number	Diff line number	Diff line
		@@ -73,6 +73,8 @@ module JsDuck
		"undefined"
		elsif this?(ast)
		:this
		elsif boolean?(ast)
		"Boolean"
		else
		:other
		end
		@@ -90,6 +92,26 @@ module JsDuck
		ast["type"] == "ThisExpression"
		end

		def boolean?(ast)
		if boolean_literal?(ast)
		true
		elsif ast["type"] == "UnaryExpression" \|\| ast["type"] == "BinaryExpression"
		!!BOOLEAN_RETURNING_OPERATORS[ast["operator"]]
		elsif ast["type"] == "LogicalExpression"
		boolean?(ast["left"]) && boolean?(ast["right"])
		elsif ast["type"] == "ConditionalExpression"
		boolean?(ast["consequent"]) && boolean?(ast["alternate"])
		elsif ast["type"] == "AssignmentExpression" && ast["operator"] == "="
		boolean?(ast["right"])
		else
		false
		end
		end

		def boolean_literal?(ast)
		ast["type"] == "Literal" && (ast["value"] == true \|\| ast["value"] == false)
		end

		def control_flow?(ast)
		CONTROL_FLOW[ast["type"]]
		end
		@@ -118,6 +140,21 @@ module JsDuck
		end
		end

		BOOLEAN_RETURNING_OPERATORS = {
		"!" => true,
		">" => true,
		">=" => true,
		"<" => true,
		"<=" => true,
		"==" => true,
		"!=" => true,
		"===" => true,
		"!==" => true,
		"in" => true,
		"instanceof" => true,
		"delete" => true,
		}

		POSSIBLY_BLOCKING = {
		"IfStatement" => true,
		"DoWhileStatement" => true,

spec/function_ast_spec.rb

+54 −0

Original line number	Diff line number	Diff line
		@@ -231,4 +231,58 @@ describe "JsDuck::FunctionAst#return_types" do
		end
		end

		describe "returns ['Boolean'] when function body" do
		it "returns true" do
		returns("/** */ function foo() { return true; }").should == ["Boolean"]
		end

		it "returns false" do
		returns("/** */ function foo() { return false; }").should == ["Boolean"]
		end

		it "returns negation" do
		returns("/** */ function foo() { return !foo; }").should == ["Boolean"]
		end

		it "returns > comparison" do
		returns("/** */ function foo() { return x > y; }").should == ["Boolean"]
		end

		it "returns <= comparison" do
		returns("/** */ function foo() { return x <= y; }").should == ["Boolean"]
		end

		it "returns == comparison" do
		returns("/** */ function foo() { return x == y; }").should == ["Boolean"]
		end

		it "returns 'in' expression" do
		returns("/** */ function foo() { return key in object; }").should == ["Boolean"]
		end

		it "returns 'instanceof' expression" do
		returns("/** */ function foo() { return obj instanceof cls; }").should == ["Boolean"]
		end

		it "returns 'delete' expression" do
		returns("/** */ function foo() { return delete foo[bar]; }").should == ["Boolean"]
		end

		it "returns conjunction of boolean expressions" do
		returns("/** */ function foo() { return x > y && y > z; }").should == ["Boolean"]
		end

		it "returns disjunction of boolean expressions" do
		returns("/** */ function foo() { return x == y \|\| y == z; }").should == ["Boolean"]
		end

		it "returns conditional expression evaluating to boolean" do
		returns("/** */ function foo() { return x ? true : a > b; }").should == ["Boolean"]
		end

		it "returns assignment of boolean" do
		returns("/** */ function foo() { return x = true; }").should == ["Boolean"]
		end
		end

		end