async load()

in fusion-plugin-i18n/src/browser.js [72:123]
45 lines of code
8 McCabe index (conditional complexity)

        async load(translationKeys) {
          const loadedKeys = Object.keys(this.translations);
          const unloaded = translationKeys.filter(key => {
            return loadedKeys.indexOf(key) < 0 && !this.requestedKeys.has(key);
          });
          if (unloaded.length > 0) {
            // Don't try to load translations again if a request is already in
            // flight. This means that we need to add unloaded chunks to
            // loadedChunks optimistically and remove them if some error happens
            unloaded.forEach(key => {
              this.requestedKeys.add(key);
            });
            const fetchOpts = {
              method: 'POST',
              headers: {
                Accept: '*/*',
                'Content-Type': 'application/json',
                ...(this.locale ? {'X-Fusion-Locale-Code': this.locale} : {}),
              },
              body: JSON.stringify(unloaded),
            };
            // TODO(#3) don't append prefix if injected fetch also injects prefix
            return fetch(
              `/_translations${
                this.locale ? `?localeCode=${this.locale}` : ''
              }`,
              fetchOpts
            )
              .then(r => {
                try {
                  return r.json();
                } catch (err) {
                  events && events.emit('i18n-load-error', {text: r.text()});
                  throw err;
                }
              })
              .then((data: {[string]: string}) => {
                for (const key in data) {
                  this.translations[key] = data[key];
                  this.requestedKeys.delete(key);
                }
              })
              .catch((err: Error) => {
                // An error occurred, so remove the chunks we were trying to load
                // from loadedChunks. This allows us to try to load those chunk
                // translations again
                unloaded.forEach(key => {
                  this.requestedKeys.delete(key);
                });
              });
          }
        }