polygerrit-ui/app/elements/shared/gr-limited-text/gr-limited-text.js

/**
 * @license
 * Copyright (C) 2017 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
(function() {
  'use strict';

  /**
    * @appliesMixin Gerrit.TooltipMixin
    */
  /*
   * The gr-limited-text element is for displaying text with a maximum length
   * (in number of characters) to display. If the length of the text exceeds the
   * configured limit, then an ellipsis indicates that the text was truncated
   * and a tooltip containing the full text is enabled.
   */
  class GrLimitedText extends Polymer.mixinBehaviors( [
    Gerrit.TooltipBehavior,
  ], Polymer.GestureEventListeners(
      Polymer.LegacyElementMixin(
          Polymer.Element))) {
    static get is() { return 'gr-limited-text'; }

    static get properties() {
      return {
      /** The un-truncated text to display. */
        text: String,

        /** The maximum length for the text to display before truncating. */
        limit: {
          type: Number,
          value: null,
        },

        /** Boolean property used by Gerrit.TooltipBehavior. */
        hasTooltip: {
          type: Boolean,
          value: false,
        },

        /**
       * Disable the tooltip.
       * When set to true, will not show tooltip even text is over limit
       */
        disableTooltip: {
          type: Boolean,
          value: false,
        },

        /**
       * The maximum number of characters to display in the tooltop.
       */
        tooltipLimit: {
          type: Number,
          value: 1024,
        },
      };
    }

    static get observers() {
      return [
        '_updateTitle(text, limit, tooltipLimit)',
      ];
    }

    /**
     * The text or limit have changed. Recompute whether a tooltip needs to be
     * enabled.
     */
    _updateTitle(text, limit, tooltipLimit) {
      // Polymer 2: check for undefined
      if ([text, limit, tooltipLimit].some(arg => arg === undefined)) {
        return;
      }

      this.hasTooltip = !!limit && !!text && text.length > limit;
      if (this.hasTooltip && !this.disableTooltip) {
        this.setAttribute('title', text.substr(0, tooltipLimit));
      } else {
        this.removeAttribute('title');
      }
    }

    _computeDisplayText(text, limit) {
      if (!!limit && !!text && text.length > limit) {
        return text.substr(0, limit - 1) + '…';
      }
      return text;
    }
  }

  customElements.define(GrLimitedText.is, GrLimitedText);
})();