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react-variable-height-infinite-scroller

3.3.5 • Public • Published

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")

install

npm i react-variable-height-infinite-scroller

Downloadsweekly downloads

29

version

3.3.5

license

ISC

homepage

github.com

repository

Gitgithub

last publish

collaborators

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