From f37150e356bc00f6bd66b988424fe06ec18c60e3 Mon Sep 17 00:00:00 2001
From: Eric Koslow <ekoslow@gmail.com>
Date: Tue, 17 Nov 2015 14:17:43 -0800
Subject: [PATCH] Automatically set srcSet attributes

This adds a new option called `srcSet` which defaults to true. When enabled, the 2x and 3x srcSet attributes will be added to rendered component. Currently, the attribute will only be added if the rendered component is an `img`.
---
 src/index.js | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/src/index.js b/src/index.js
index 6ab5d7052..39dba9441 100644
--- a/src/index.js
+++ b/src/index.js
@@ -35,7 +35,8 @@ export default class ReactImgix extends Component {
     fluid: PropTypes.bool,
     children: PropTypes.any,
     customParams: PropTypes.object,
-    entropy: PropTypes.bool
+    entropy: PropTypes.bool,
+    srcSet: PropTypes.bool,
   }
   static defaultProps = {
     precision: 100,
@@ -45,7 +46,8 @@ export default class ReactImgix extends Component {
     faces: true,
     fit: 'crop',
     entropy: false,
-    auto: ['format']
+    auto: ['format'],
+    srcSet: true,
   }
   state = {
     width: null,
@@ -64,6 +66,7 @@ export default class ReactImgix extends Component {
 
   render () {
     let src = ''
+    let srcSet = ''
     let component = this.props.component
 
     let width = this._findSizeForDimension('width')
@@ -78,14 +81,19 @@ export default class ReactImgix extends Component {
     if (this.props.fit) fit = this.props.fit
 
     if (this.state.mounted || this.props.aggresiveLoad) {
-      src = processImage(this.props.src, {
+      const srcOptions = {
         auto: this.props.auto,
         ...this.props.customParams,
         crop,
         fit,
         width,
         height
-      })
+      }
+      
+      src = processImage(this.props.src, srcOptions)
+      const dpr2 = processImage(this.props.src, {...srcOptions, dpr: 2})
+      const dpr3 = processImage(this.props.src, {...srcOptions, dpr: 3})
+      srcSet = `${dpr2} 2x, ${dpr3} 3x`
     }
 
     let childProps = {...this.props}
@@ -100,10 +108,16 @@ export default class ReactImgix extends Component {
         backgroundSize: 'cover'
       }
       delete childProps.src
+      delete childProps.srcSet
     } else {
       if (!this.props.component) {
         component = 'img'
       }
+      
+      if (component === 'img' && this.props.srcSet) {
+        childProps.srcSet = srcSet
+      }
+      
       childProps.src = src
     }
     return React.createElement(component,