contentful suggestions function

contentful-suggestions-function.ts

async fetchSuggestions(tags: string[], currentArticleSlug: string) {

    const limit = 3; // limit of posts we want to fetch
    let entries = [];

    const initialOptions = {
        content_type: CONTENT_TYPE_BLOGPOST,
        limit,
        // find at least one matching tag, else undefined properties are not copied
        'fields.tags.sys.id[in]': tags.length ? tags.join(',') : undefined,
        'fields.slug[ne]': currentArticleSlug, // exclude current article
    };

    try {

        const suggestionsByTags = await this.client.getEntries(initialOptions);

        entries = suggestionsByTags.items;
        // number of suggestions by tag is less than the limit
        if (suggestionsByTags.total < limit) {
            // exclude already picked slugs
            const slugsToExclude = [...suggestionsByTags.items, {fields: {slug: currentArticleSlug}}]
                .map((item: { fields: any }) => item.fields.slug)
                .join(',');

            // fetch random suggestions
            const randomSuggestions = await this.client.getEntries({
                content_type: CONTENT_TYPE_BLOGPOST,
                limit: limit - suggestionsByTags.total,
                'fields.slug[nin]': slugsToExclude, // exclude slugs already fetched
            });

            entries = [...entries, ...randomSuggestions.items];

        }

        entries = this.mapData(entries);

        return entries;
    } catch (e) {
        console.error(e);
    }
}