我得到这个编译错误在我的Typescript代码：
元素隐式具有“any”类型，因为索引表达式不是“number”类型。typescript（7015）

export class OntologyFunctions {

    // function to clear selected properties
    @OntologyEditFunction()
    public async cancelmanualrc(
        missingpart: OanalyticsMissingPartsRca[],
        propertiesToClear: string[]
    ): Promise<void> {

        var x = "";
        var key_aligned;
        for (const key of propertiesToClear) {

            key_aligned = COLUMN_MISSING_PART_REMPLACE[key as typeof x];
            
            missingpart[key_aligned as keyof ObjectPartsNew] = undefined;
            
        }
    }
}