js: reorganize Javascript file structure.

Move Javascript files from app/components/**/*.js back to app/javascript/src/javascripts/*.js.
This way Javascript files are in one place, which simplifies import paths and makes it
easier to see all Javascript at once.

app/components/file_upload_component/file_upload_component.js

@@ -1,163 +0,0 @@
-import Dropzone from 'dropzone';
-import Utility from "../../javascript/src/javascripts/utility.js";
-import capitalize from "lodash/capitalize";
-
-export default class FileUploadComponent {
-  static initialize() {
-    $(".file-upload-component").toArray().forEach(element => {
-      new FileUploadComponent($(element));
-    });
-  }
-
-  constructor($component) {
-    this.$component = $component;
-    this.$component.on("ajax:success", e => this.onSubmit(e));
-    this.$component.on("ajax:error", e => this.onError(e));
-    this.$dropTarget.on("paste.danbooru", e => this.onPaste(e));
-    this.dropzone = this.initializeDropzone();
-
-    // If the source field is pre-filled, then immediately submit the upload.
-    if (/^https?:\/\//.test(this.$sourceField.val())) {
-      this.$component.find("input[type='submit']").click();
-    }
-  }
-
-  initializeDropzone() {
-    if (!window.FileReader) {
-      this.$dropzone.addClass("hidden");
-      this.$component.find("input[type='file']").removeClass("hidden");
-      return null;
-    }
-
-    let dropzone = new Dropzone(this.$dropTarget.get(0), {
-      url: "/uploads.json",
-      paramName: "upload[file]",
-      clickable: this.$dropzone.get(0),
-      previewsContainer: this.$dropzone.get(0),
-      thumbnailHeight: null,
-      thumbnailWidth: null,
-      addRemoveLinks: false,
-      maxFiles: 1,
-      maxFilesize: this.maxFileSize,
-      maxThumbnailFilesize: this.maxFileSize,
-      timeout: 0,
-      acceptedFiles: "image/jpeg,image/png,image/gif,video/mp4,video/webm",
-      previewTemplate: this.$component.find(".dropzone-preview-template").html(),
-    });
-
-    dropzone.on("complete", file => {
-      this.$dropzone.find(".dz-progress").hide();
-    });
-
-    dropzone.on("addedfile", file => {
-      this.$dropzone.removeClass("error");
-      this.$dropzone.find(".dropzone-hint").hide();
-
-      // Remove all files except the file just added.
-      dropzone.files.forEach(f => {
-        if (f !== file) {
-          dropzone.removeFile(f);
-        }
-      });
-    });
-
-    dropzone.on("success", file => {
-      this.$dropzone.addClass("success");
-      let upload = JSON.parse(file.xhr.response)
-      this.pollStatus(upload);
-    });
-
-    dropzone.on("error", (file, msg) => {
-      this.$dropzone.addClass("error");
-    });
-
-    return dropzone;
-  }
-
-  onPaste(e) {
-    let url = e.originalEvent.clipboardData.getData("text");
-    this.$component.find("input[name='upload[source]']:not([disabled])").val(url);
-
-    if (/^https?:\/\//.test(url)) {
-      this.$component.find("input[type='submit']:not([disabled])").click();
-    }
-
-    e.preventDefault();
-  }
-
-  onSubmit(e) {
-    let upload = e.originalEvent.detail[0];
-    this.pollStatus(upload);
-  }
-
-  // Called after the upload is submitted via AJAX. Polls the upload until it
-  // is complete, then redirects to the upload page.
-  async pollStatus(upload) {
-    this.$component.find("progress").removeClass("hidden");
-    this.$component.find("input").attr("disabled", "disabled");
-
-    while (upload.status === "pending" || upload.status === "processing") {
-      await Utility.delay(500);
-      upload = await $.get(`/uploads/${upload.id}.json`);
-    }
-
-    if (upload.status === "completed") {
-      let params = new URLSearchParams(window.location.search);
-      let isBookmarklet = params.has("url");
-      params.delete("url");
-      params.delete("ref");
-
-      let url = new URL(`/uploads/${upload.id}`, window.location.origin);
-      url.search = params.toString();
-
-      if (isBookmarklet) {
-        window.location.replace(url);
-      } else {
-        window.location.assign(url);
-      }
-    } else if (upload.status === "error") {
-      this.$dropzone.removeClass("success");
-      this.$component.find("progress").addClass("hidden");
-      this.$component.find("input").removeAttr("disabled");
-
-      Utility.error(`Upload failed: ${upload.error}.`);
-    }
-  }
-
-  // Called when creating the upload failed because of a validation error (normally, because the source URL was not a real URL).
-  async onError(e) {
-    let errors = e.originalEvent.detail[0].errors;
-    let message = Object.keys(errors).map(attribute => {
-      return errors[attribute].map(error => {
-        if (attribute === "base") {
-          return `${error}`;
-        } else {
-          return `${capitalize(attribute)} ${error}`;
-        }
-      });
-    }).join("; ");
-
-    Utility.error(message);
-  }
-
-  get $dropzone() {
-    return this.$component.find(".dropzone-container");
-  }
-
-  get $sourceField() {
-    return this.$component.find("input[name='upload[source]']");
-  }
-
-  get maxFileSize() {
-    return Number(this.$component.attr("data-max-file-size")) / (1024 * 1024);
-  }
-
-  // The element to listen for drag and drop events and paste events. By default,
-  // it's the `.file-upload-component` element. If `data-drop-target` is the `body`
-  // element, then you can drop images or paste URLs anywhere on the page.
-  get $dropTarget() {
-    return $(this.$component.attr("data-drop-target") || this.$component);
-  }
-}
-
-$(FileUploadComponent.initialize);