typescript.md

TypeScript Cheatsheet

1. use never isntead of unknown whenever possible

2. Last resort pseudo-any types:

   export type EnumType = { [key: string]: string };
   export type ObjectType = { [key: string]: unknown | unknown[] };

3. An example of looping through an object's keys in the actual code:

   export const as = (table: string, sqlFields: EnumType, fields: EnumType) => {
     let output: string[] = [];
   
     for (const i in sqlFields) {
       const row = `${table}.${sqlFields[i]} as ${fields[i]}`;
       output.push(row);
     }
     return output;
   };

4. Make an object immutable

   const obj = {
     foo: 'bar'
   } as const

5. Required<...> is the opposite of Partial<...>

6. protected methods of TS classes are private, but accessible by child classes