labelSyncer.ts

import { Octokit } from "octokit";

export class Label {
    id: number;
    node_id: string;
    url: string;
    name: string;
    description: string | null;
    color: string;
    default: boolean;
}

export class LabelSyncer {
    public static syncLabels(octokit_source: Octokit, octokit_target: Octokit, owner_source: string, repo_source: string, owner_target:string, repo_target:string):Promise<void> {
        // Retrieve labels in source repo
        let sourceRepoLabels: Label[] = [];
        return octokit_source.request('GET /repos/{owner}/{repo}/labels', {
            owner: owner_source,
            repo: repo_source,
        }).then((response) => {
            sourceRepoLabels = response.data;
        }).catch((err) => {
            console.error("Failed to retrieve source repo labels", err);
        }).then(() => {
            // Retrieve labels in target repo
            let targetRepoLabels: Label[] = [];
            octokit_target.request('GET /repos/{owner}/{repo}/labels', {
                owner: owner_target,
                repo: repo_target,
            }).then((response) => {
                targetRepoLabels = response.data;
            }).catch((err) => {
                console.error("Failed to retrieve target repo labels", err);
            }).then(() => {
                // Filter source repo labels: remove all that from list that are already contained in target (= delta)
                sourceRepoLabels = sourceRepoLabels
                .filter((label) => targetRepoLabels
                // Match by name and description, as IDs may vary across repos
                .find(targetEntry => targetEntry.name == label.name && targetEntry.description == label.description)
                == undefined
                );
                
                // Create delta of missing issues in target
                Promise.all(
                    sourceRepoLabels.map(element => {
                        return octokit_target.request('POST /repos/{owner}/{repo}/labels', {
                            owner: owner_target,
                            repo: repo_target,
                            name: element.name,
                            description: element.description ? element.description : "",
                            color: element.color
                        }).then(() => "Successfully synced label " + element.name)
                        .catch((err) => "Failed to sync label " + element.name + ": " + err);
                    })
                    ).then((results) => {
                        results.forEach((element) => console.log(element));
                    }).then(() => {
                        console.log("Done");
                        return null;
                    });
                });
            });    
        }
}