# All files / src simpleImgProvider.js

100% Statements 17/17
100% Branches 5/5
100% Functions 10/10
100% Lines 17/17

    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    13
    14
    15
    16
    17
    18
    19
    20
    21
    22
    23
    24
    25
    26
    27
    28
    29
    30
    31
    32
    33
    34
    35
    36
    37
    38
    39
    40
    41
    42
    43
    44
    45
    46
    47
    48
    49
    50
    51
    52
    53
    54
    55
    56
    57
    58
    59
    60
    61
    62
    63
    64
    65
    66
    67
    68
    69
    70
    71
    72
    73
    74
    75
    76
    77
    78
    79
    80
    81
    82
    83
    84
    85
    86
    87
    88
    89
    90
    91
    92
    93
    94
    95
    96
    97
    98
    99
    100
    101
    102

    2x

    10x

    10x
    6x

    4x
    1x
    1x

    1x

    1x

    1x

    3x
    3x
    3x
    3x

    1x

    1x

    17x

     // @flow
    import React from 'react';
    import observerStart, { defaultConfig } from './logic/observerStart';

    // $FlowIgnoreLine:
    export const SimpleImgContext = React.createContext({});

    type State = {
      mountedImages: Set<any>,
      isContextDocumentLoad: boolean,
    };

    export type Config = {
      root?: HTMLElement,
      rootMargin?: string,
      threshold?: number | Array<number>,
    };

    type Props = {
      config?: Object,
      children: any,
    };

    export default class SimpleImgProvider extends React.Component<Props, State> {
      static displayName = 'SimpleImgProvider';

      static defaultProps = {
        config: defaultConfig,
      };

      state: State = {
        mountedImages: new Set(),
        isContextDocumentLoad: false,
      };

      observer = {};

      imageLoadRefs: Set<any> = new Set();

      componentDidMount() {
        const { config } = this.props;

        if (document.readyState === 'complete') {
          this.observer = observerStart.call(this, config);
        } else {
          window.addEventListener('load', () => {
            this.observer = observerStart.call(this, config);
            this.setState({
              isContextDocumentLoad: true,
            });
          });
        }
      }

      componentWillUnmount() {
        this.imageLoadRefs.forEach(image => {
          // cancel all loading images;
          image.src = ''; // eslint-disable-line no-param-reassign
        });
      }

      appendImageRef = (image: HTMLElement) => this.observer && this.observer.observe && this.observer.observe(image);

      removeImageRef = (image: HTMLElement) => {
        // $FlowIgnoreLine:
        this.observer.unobserve(image);
        this.setState(({ mountedImages }) => {
          mountedImages.delete(image);
          return {
            mountedImages,
          };
        });
      };

      appendImgLoadingRef = (image: HTMLElement) => {
        this.imageLoadRefs.add(image);
      };

      removeImgLoadingRef = (image: HTMLElement) => {
        this.imageLoadRefs.delete(image);
      };

      render() {
        return (
          <SimpleImgContext.Provider
            value={{
              ...{
                ...this.state,
                useContext: true,
                appendImageRef: this.appendImageRef,
                removeImageRef: this.removeImageRef,
                appendImgLoadingRef: this.appendImgLoadingRef,
                removeImgLoadingRef: this.removeImgLoadingRef,
              },
            }}
          >
            {this.props.children}
          </SimpleImgContext.Provider>
        );
      }
    }