# DGM Interview with Cagatay

## Implementation Challenge: Data Conversion

You're migrating data from one CMS to another, and the origin CMS stores a page layout with a type like this:

interface SrcComponentInstance {
    // the name of the target component
    name: string;
    // arguments given to the component
    args: {
        // name of the argument
        name: string;
        // value of the argument
        value: JSONValue;
    }[];
    // the contents of the component
    contents: (SrcComponentInstance | string)[];
};

The target CMS uses a different approach, giving a unique identifier to every single component and text snippet and using those references.

type Id = string;
type Language = 'eng' | 'fra' | 'spa';
interface DestComponentInstance {
    // unique identifier for this component
    id: Id;
    // the name of the target component
    name: string;
    // the arugements given to the component
    args: {[k in string]?: JSONValue};
    // the ids of each child instance of the component
    contents: Id[];
};
interface DestTextInstance {
    // unique identifier for this text
    id: Id;
    // the content text, depending on the language
    content: {[k in Language]?: string};
};

Write a function that converts a list of top level `SrcComponentInstance`s to `DestComponentInstance`s:

const textInstances: DestTextInstance[] = []

const convertSrcToDestInstance = (src: SrcComponentInstance, id?: Id): DestComponentInstance[] => {
    const results: DestComponentInstance[] = []
    results.push({
        id: id || generateId(),
        name: src.name,
        args: src.args.reduce((result, arg) => {
            result[arg.name] = arg.value;
            return result;
        }, {}),
        contents: src.contents.map(content => {
            const id = generateId()
            if (typeof content === 'string') {
                textInstances.push({
                    id,
                    contents: {
                        eng: content,
                        spa: translate('spa', content),
                    }
                })
            }
            
            results.push(...convertSrcToDestInstance(content, id))
            
            return id
        })
    })
    
    return results
}
const convert = (src: SrcComponentInstance[]): {[id in string]?: DestComponentInstance} => {
    
}