react-variable-height-infinite-scroller

react-variable-height-infinite-scroller

An infinite scroller especially made for variable row heights (no precomputation of row height necessary).

See a Demo

Why

Because sometimes you don't know the size of the rows you're going to render before rendering

Install:

npm i --save react-variable-height-infinite-scroller

Usage:

<InfiniteScroller
  averageElementHeight={100} // this is a guess you make!
  containerHeight={600}
  rowToJumpTo={rowToJumpTo} // (optional) set this if you want to start/jump to a a particular row. Must be passed as a new object each time to allow for difference checking
  renderRow={renderRow} // function to render a row
  totalNumberOfRows={fakeRows.length} // an array of data for your rows
/>

Props

Name	Default	Description
containerHeight number	required	Maximum height of the scroll container
totalNumberOfRows number	required	Length of the data array
renderRow function	required	Function to render a row
averageElementHeight number	(optional) 100	This is a guess you make of what the average row height will be height. This is used to approximate how far to move the scrollbar
rowToJumpTo	(optional) 0	Object of shape { row: Number }. Row you want to start with or jump to. Must be passed as a new object each time to allow for difference checking
jumpToBottomOfRow boolean	(optional) false	By default jumping to a row jumps to the top. Set to true if you want to jump to the bottom of the row
containerClassName string	(optional) infiniteContainer	className to apply on container
onScroll function	(optional) no-op	Hook to call on scroll

Methods

Name	Description
scrollTo	Alternate way to jump to a particular row. Usage below.

scrollTo usage*:

class MyComponent extends Component {
  scrollSomewhere() {
    this.list.scrollTo(Math.floor(Math.random() * 100));
  }

  render() {
    return (
      <div>
        Here is my list:
        <InfiniteScroller length={100} itemRenderer={...} ref={c => this.list = c} />
        <button onClick={::this.scrollSomewhere}>Scroll Somewhere</button>
      </div>
    );
  }
}

Taken from the demo code:

import React from 'react';
import InfiniteScroller from './InfiniteScroller.js';

function getFakeRowsWithHeights(numberOfRows) {
  let newFakeRows = [];
  for (let i = 0; i < numberOfRows; i++) {
    newFakeRows.push({height: Math.floor(1000 * Math.random())});
  }
  return newFakeRows;
}

const Example1 = React.createClass({
  getNewRandomRow(totalRows) {
    return {row: Math.floor(totalRows * Math.random())};
  },

  getInitialState() {
    const newNumberOfRowsToDisplay = Math.floor(Math.random() * 200);
    const newFakeRows = getFakeRowsWithHeights(newNumberOfRowsToDisplay);
    return {
      rowToJumpTo: null,
      newRowToJumpTo: this.getNewRandomRow(newFakeRows.length),
      fakeRows: newFakeRows,
    };
  },
  render() {
    const newNumberOfRowsToDisplay = Math.floor(Math.random() * 200);
    return (
      <div style={{width: 300}} overflow="scroll">
        <h3>
        Example 1: Random number of rows and row heights
        </h3>
        <button onClick={() => {
          this.setState({
            rowToJumpTo: this.state.newRowToJumpTo,
            newRowToJumpTo: this.getNewRandomRow(this.state.fakeRows.length),
          });
        }}>
          Jump to a random row: Row #{this.state.newRowToJumpTo.row} (its height is {this.state.fakeRows[this.state.newRowToJumpTo.row].height})
        </button>
        <button onClick={() => {
          const newFakeRows = getFakeRowsWithHeights(newNumberOfRowsToDisplay);
          this.setState({
            fakeRows: newFakeRows,
            newRowToJumpTo: this.getNewRandomRow(newFakeRows.length),
          });
        }}>
          Create {newNumberOfRowsToDisplay} new rows
        </button>

        <InfiniteScroller
          averageElementHeight={100} // this is a guess you make!
          containerHeight={600}
          rowToJumpTo={this.state.rowToJumpTo} // (optional) set this if you want to start/jump to a a particular row. Must be passed as a new object each time to allow for difference checking
          renderRow={this.renderRow} // function to render a row
          totalNumberOfRows={this.state.fakeRows.length} // an array of data for your rows
        />
      </div>
    );
  },

  renderRow(rowNumber) {
    const heightOfRow = this.state.fakeRows[rowNumber].height;
    return (
      <div
        key={rowNumber}
        style={{height: heightOfRow, background: rowNumber % 2 === 0 ? 'red' : 'orange'}}
      >
        Height: {heightOfRow}
        <br/>
        Row Number: {rowNumber}
      </div>
    );
  },
});

React.render(<Example1 />, document.getElementById('container'));

Contributing

Changelog is now autogenerated. So commits have to be prefixed by one the four following prefixes to get added to the changelog:

• [added] added a new feature
• [changed] changed an existing feature
• [fixed] fixed a bug
• [removed] removed something or a file

Run npm test to lint

#Changelog: Changelog

*(taken from "react-list")