muerwre.github.io/docs/api/_content/query/iZIUw8pCoM.json

{"_path":"/typescript/type-guards","_dir":"typescript","_draft":false,"_partial":false,"_locale":"en","_empty":false,"title":"Type Guards","description":"Useful for type checking at compile and run time:","excerpt":{"type":"root","children":[{"type":"element","tag":"p","props":{},"children":[{"type":"text","value":"Useful for type checking at compile and run time:"}]},{"type":"element","tag":"code","props":{"code":"function isFish(pet: Fish | Bird): pet is Fish {\n  return (pet as Fish).swim !== undefined;\n}\n","language":"typescript"},"children":[{"type":"element","tag":"pre","props":{},"children":[{"type":"element","tag":"code","props":{"__ignoreMap":""},"children":[{"type":"text","value":"function isFish(pet: Fish | Bird): pet is Fish {\n  return (pet as Fish).swim !== undefined;\n}\n"}]}]}]},{"type":"element","tag":"p","props":{},"children":[{"type":"text","value":"Usage:"}]},{"type":"element","tag":"code","props":{"code":"const pet = getSmallPet();\n \nif (isFish(pet)) {\n  pet.swim();\n} else {\n  pet.fly();\n}\n","language":"typescript"},"children":[{"type":"element","tag":"pre","props":{},"children":[{"type":"element","tag":"code","props":{"__ignoreMap":""},"children":[{"type":"text","value":"const pet = getSmallPet();\n \nif (isFish(pet)) {\n  pet.swim();\n} else {\n  pet.fly();\n}\n"}]}]}]}]},"body":{"type":"root","children":[{"type":"element","tag":"p","props":{},"children":[{"type":"text","value":"Useful for type checking at compile and run time:"}]},{"type":"element","tag":"code","props":{"code":"function isFish(pet: Fish | Bird): pet is Fish {\n  return (pet as Fish).swim !== undefined;\n}\n","language":"typescript"},"children":[{"type":"element","tag":"pre","props":{},"children":[{"type":"element","tag":"code","props":{"__ignoreMap":""},"children":[{"type":"element","tag":"span","props":{"class":"line"},"children":[{"type":"element","tag":"span","props":{"class":"ct-c77a48"},"children":[{"type":"text","value":"function"}]},{"type":"element","tag":"span","props":{"class":"ct-fd17a7"},"children":[{"type":"text","value":" "}]},{"type":"element","tag":"span","props":{"class":"ct-065d68"},"children":[{"type":"text","value":"isFish"}]},{"type":"element","tag":"span","props":{"class":"ct-fd17a7"},"children":[{"type":"text","value":"("}]},{"type":"element","tag":"span","props":{"class":"ct-9b0c86"},"children":[{"type":"text","value":"pet"}]},{"type":"element","tag":"span","props":{"class":"ct-159293"},"children":[{"type":"text","value":":"}]},{"type":"element","tag":"span","props":{"class":"ct-fd17a7"},"children":[{"type":"text","value":" "}]},{"type":"element","tag":"span","props":{"class":"ct-417de1"},"children":[{"type":"text","value":"Fish"}]},{"type":"element","tag":"span","props":{"class":"ct-fd17a7"},"children":[{"type":"text","value":" "}]},{"type":"element","tag":"span","props":{"class":"ct-159293"},"children":[{"type":"text","value":"|"}]},{"type":"element","tag":"span","props":{"class":"ct-fd17a7"},"children":[{"type":"text","value":" "}]},{"type":"element","tag":"span","props":{"class":"ct-417de1"},"children":[{"type":"text","value":"Bird"}]},{"type":"element","tag":"span","props":{"class":"ct-fd17a7"},"children":[{"type":"text","value":")"}]},{"type":"element","tag":"span","props":{"class":"ct-159293"},"children":[{"type":"text","value":":"}]},{"type":"element","tag":"span","props":{"class":"ct-fd17a7"},"children":[{"type":"text","value":" "}]},{"type":"element","tag":"span","props":{"class":"ct-9b0c86"},"children":[{"type":"text","value":"pet"}]},{"type":"element","tag":"span","props":{"class":"ct-fd17a7"},"children":[{"type":"text","value":" "}]},{"type":"element","tag":"span","props":{"class":"ct-159293"},"children":[{"type":"text","value":"is"}]},{"type":"element","tag":"span","props":{"class":"ct-fd17a7"},"children":[{"type":"text","value":" "}]},{"type":"element","tag":"span","props":{"class":"ct-417de1"},"children":[{"type":"text","value":"Fish"}]},{"type":"element","tag":"span","props":{"class":"ct-fd17a7"},"children":[{"type":"text","value":" {"}]}]},{"type":"element","tag":"span","props":{"class":"line"},"children":[{"type":"element","tag":"span","props":{"class":"ct-1e77de"},"children":[{"type":"text","value":"  "}]},{"type":"element","tag":"span","props":{"class":"ct-42123c"},"children":[{"type":"text","value":"return"}]},{"type":"element","tag":"span","props":{"class":"ct-1e77de"},"children":[{"type":"text","value":" ("}]},{"type":"element","tag":"span","props":{"class":"ct-126cc2"},"children":[{"type":"text","value":"pet"}]},{"type":"element","tag":"span","props":{"class":"ct-1e77de"},"children":[{"type":"text","value":" "}]},{"type":"element","tag":"span","props":{"class":"ct-42123c"},"children":[{"type":"text","value":"as"}]},{"type":"element","tag":"span","props":{"class":"ct-1e77de"},"children":[{"type":"text","value":" "}]},{"type":"element","tag":"span","props":{"class":"ct-dc808b"},"children":[{"type":"text","value":"Fish"}]},{"type":"element","tag":"span","props":{"class":"ct-1e77de"},"children":[{"type":"text","value":")."}]},{"type":"element","tag":"span","props":{"class":"ct-126cc2"},"children":[{"type":"text","value":"swim"}]},{"type":"element","tag":"span","props":{"class":"ct-1e77de"},"children":[{"type":"text","value":" "}]},{"type":"element","tag":"span","props":{"class":"ct-42123c"},"children":[{"type":"text","value":"!=="}]},{"type":"element","tag":"span","props":{"class":"ct-1e77de"},"children":[{"type":"text","value":" "}]},{"type":"element","tag":"span","props":{"class":"ct-4c8c5d"},"children":[{"type":"text","value":"undefined"}]},{"type":"element","tag":"span","props":{"class":"ct-1e77de"},"children":[{"type":"text","value":";"}]}]},{"type":"element","tag":"span","props":{"class":"line"},"children":[{"type":"element","tag":"span","props":{"class":"ct-1e77de"},"children":[{"type":"text","value":"}"}]}]}]}]}]},{"type":"element","tag":"p","props":{},"children":[{"type":"text","value":"Usage:"}]},{"type":"element","tag":"code","props":{"code":"const pet = getSmallPet();\n \nif (isFish(pet)) {\n  pet.swim();\n} else {\n  pet.fly();\n}\n","language":"typescript"},"children":[{"type":"element","tag":"pre","props":{},"children":[{"type":"element","tag":"code","props":{"__ignoreMap":""},"children":[{"type":"element","tag":"span","props":{"class":"line"},"children":[{"type":"element","tag":"span","props":{"class":"ct-6c7ab9"},"children":[{"type":"text","value":"const"}]},{"type":"element","tag":"span","props":{"class":"ct-1e77de"},"children":[{"type":"text","value":" "}]},{"type":"element","tag":"span","props":{"class":"ct-600790"},"children":[{"type":"text","value":"pet"}]},{"type":"element","tag":"span","props":{"class":"ct-1e77de"},"children":[{"type":"text","value":" "}]},{"type":"element","tag":"span","props":{"class":"ct-42123c"},"children":[{"type":"text","value":"="}]},{"type":"element","tag":"span","props":{"class":"ct-1e77de"},"children":[{"type":"text","value":" "}]},{"type":"element","tag":"span","props":{"class":"ct-ae3d89"},"children":[{"type":"text","value":"getSmallPet"}]},{"type":"element","tag":"span","props":{"class":"ct-1e77de"},"children":[{"type":"text","value":"();"}]}]},{"type":"element","tag":"span","props":{"class":"line"},"children":[{"type":"element","tag":"span","props":{"class":"ct-1e77de"},"children":[{"type":"text","value":" "}]}]},{"type":"element","tag":"span","props":{"class":"line"},"children":[{"type":"element","tag":"span","props":{"class":"ct-42123c"},"children":[{"type":"text","value":"if"}]},{"type":"element","tag":"span","props":{"class":"ct-1e77de"},"children":[{"type":"text","value":" ("}]},{"type":"element","tag":"span","props":{"class":"ct-ae3d89"},"children":[{"type":"text","value":"isFish"}]},{"type":"element","tag":"span","props":{"class":"ct-1e77de"},"children":[{"type":"text","value":"("}]},{"type":"element","tag":"span","props":{"class":"ct-126cc2"},"children":[{"type":"text","value":"pet"}]},{"type":"element","tag":"span","props":{"class":"ct-1e77de"},"children":[{"type":"text","value":")) {"}]}]},{"type":"element","tag":"span","props":{"class":"line"},"children":[{"type":"element","tag":"span","props":{"class":"ct-1e77de"},"children":[{"type":"text","value":"  "}]},{"type":"element","tag":"span","props":{"class":"ct-126cc2"},"children":[{"type":"text","value":"pet"}]},{"type":"element","tag":"span","props":{"class":"ct-1e77de"},"children":[{"type":"text","value":"."}]},{"type":"element","tag":"span","props":{"class":"ct-ae3d89"},"children":[{"type":"text","value":"swim"}]},{"type":"element","tag":"span","props":{"class":"ct-1e77de"},"children":[{"type":"text","value":"();"}]}]},{"type":"element","tag":"span","props":{"class":"line"},"children":[{"type":"element","tag":"span","props":{"class":"ct-1e77de"},"children":[{"type":"text","value":"} "}]},{"type":"element","tag":"span","props":{"class":"ct-42123c"},"children":[{"type":"text","value":"else"}]},{"type":"element","tag":"span","props":{"class":"ct-1e77de"},"children":[{"type":"text","value":" {"}]}]},{"type":"element","tag":"span","props":{"class":"line"},"children":[{"type":"element","tag":"span","props":{"class":"ct-1e77de"},"children":[{"type":"text","value":"  "}]},{"type":"element","tag":"span","props":{"class":"ct-126cc2"},"children":[{"type":"text","value":"pet"}]},{"type":"element","tag":"span","props":{"class":"ct-1e77de"},"children":[{"type":"text","value":"."}]},{"type":"element","tag":"span","props":{"class":"ct-ae3d89"},"children":[{"type":"text","value":"fly"}]},{"type":"element","tag":"span","props":{"class":"ct-1e77de"},"children":[{"type":"text","value":"();"}]}]},{"type":"element","tag":"span","props":{"class":"line"},"children":[{"type":"element","tag":"span","props":{"class":"ct-1e77de"},"children":[{"type":"text","value":"}"}]}]}]}]}]},{"type":"element","tag":"style","children":[{"type":"text","value":".ct-ae3d89{color:#D2A8FF}.ct-600790{color:#79C0FF}.ct-6c7ab9{color:#FF7B72}.ct-4c8c5d{color:#79C0FF}.ct-dc808b{color:#FFA657}.ct-126cc2{color:#C9D1D9}.ct-42123c{color:#FF7B72}.ct-1e77de{color:#C9D1D9}.ct-417de1{color:#FFA657}.ct-159293{color:#FF7B72}.ct-9b0c86{color:#FFA657}.ct-065d68{color:#D2A8FF}.ct-fd17a7{color:#C9D1D9}.ct-c77a48{color:#FF7B72}.light .ct-c77a48{color:#073642}.light .ct-fd17a7{color:#657B83}.light .ct-065d68{color:#268BD2}.light .ct-9b0c86{color:#657B83}.light .ct-159293{color:#859900}.light .ct-417de1{color:#268BD2}.light .ct-1e77de{color:#657B83}.light .ct-42123c{color:#859900}.light .ct-126cc2{color:#268BD2}.light .ct-dc808b{color:#268BD2}.light .ct-4c8c5d{color:#B58900}.light .ct-6c7ab9{color:#073642}.light .ct-600790{color:#268BD2}.light .ct-ae3d89{color:#268BD2}"}]}],"toc":{"title":"","searchDepth":2,"depth":2,"links":[]}},"_type":"markdown","_id":"content:Typescript:Type guards.md","_source":"content","_file":"Typescript/Type guards.md","_extension":"md"}