Typescript is obscurely particular with accessing attribute keys on objects that lack a generic signature. Adding generic signatures reduces type-safety though.
Here’s a Typescript-friendly way to verify an attribute exists in an object, and then access that attribute.
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// implicitly typed object const myObj = { Hello: "world" }; const myObjKey = "Hello"; // The commonly recommended way to check if an attribute exists, // which throws a no signature lint error Element implicitly // has any type (TS7053) in Typescript // // if (myObj[myObjKey]) { // ... // } // The 'in' way, which Typescript likes if (myObjKey in myObj) { // Now that we've confirmed the attribute exists, it's // type-safe to recast myObjKey and access it as an attribute console.log(myObj[myObjKey as keyof typeof myObj]); } |
This post originally posted at https://blog.smartlogic.io/accessing-object-attributes-based-on-a-variable-in-typescript/