Certain modifiers cannot be used in certain positions, for example, the async
modifier cannot be used in a leading space on a class field:
class A {
async prop!: () => Promise<string>;
async prop2 = () => "string";
}Fix: Move modifier to a valid location.
Remove the async modifier, or move it to the value instead of the property:
class A {
prop!: () => Promise<string>;
prop2 = async () => "string";
}Related: TS1040