feat(gatsby-plugin-sharp): add defaultQuality option

* Add defaultQuality option to gatsby-plugin-sharp

* Update docs for defaultQuality option

* Remove default quality value from gatsby-transformer-sharp

* Remove check for gatsby-tranformer-sharp default quality value

* Update setting a default quality in README

Co-Authored-By: sbardian <sbardian@gmail.com>

Author: sbardian

packages/gatsby-plugin-sharp/README.md

@@ -32,6 +32,7 @@ plugins: [
     options: {
       useMozJpeg: false,
       stripMetadata: true,
+      defaultQuality: 75,
     },
   },
 ]
@@ -249,6 +250,10 @@ fixed(
 }
 ```
 
+### Setting a default quality
+
+You can pass a default image quality to `sharp` by setting the `defaultQuality` option.
+
 ### Using MozJPEG
 
 You can opt-in to use [MozJPEG][16] for jpeg-encoding. MozJPEG provides even

packages/gatsby-plugin-sharp/src/index.js

@@ -45,6 +45,7 @@ exports.setBoundActionCreators = actions => {
 const pluginDefaults = {
   useMozJpeg: process.env.GATSBY_JPEG_ENCODER === `MOZJPEG`,
   stripMetadata: true,
+  defaultQuality: 50,
 }
 let pluginOptions = Object.assign({}, pluginDefaults)
 exports.setPluginOptions = opts => {
@@ -95,8 +96,8 @@ const generalArgs = {
   sizeByPixelDensity: false,
 }
 
-const healOptions = (args, defaultArgs) => {
-  let options = _.defaults({}, args, defaultArgs, generalArgs)
+const healOptions = ({ defaultQuality: quality }, args, defaultArgs) => {
+  let options = _.defaults({}, args, { quality }, defaultArgs, generalArgs)
   options.quality = parseInt(options.quality, 10)
   options.pngCompressionLevel = parseInt(options.pngCompressionLevel, 10)
   options.pngCompressionSpeed = parseInt(options.pngCompressionSpeed, 10)
@@ -125,7 +126,6 @@ const healOptions = (args, defaultArgs) => {
 
 let totalJobs = 0
 const processFile = (file, jobs, cb, reporter) => {
-  // console.log("totalJobs", totalJobs)
   bar.total = totalJobs
 
   let imagesFinished = 0
@@ -372,7 +372,7 @@ const queueJob = (job, reporter) => {
 }
 
 function queueImageResizing({ file, args = {}, reporter }) {
-  const options = healOptions(args, {})
+  const options = healOptions(pluginOptions, args, {})
   // Filter out false args, and args not for this extension and put width at
   // end (for the file path)
   const pairedArgs = _.toPairs(args)
@@ -476,7 +476,7 @@ function queueImageResizing({ file, args = {}, reporter }) {
 }
 
 async function generateBase64({ file, args, reporter }) {
-  const options = healOptions(args, { width: 20 })
+  const options = healOptions(pluginOptions, args, { width: 20 })
   let pipeline
   try {
     pipeline = sharp(file.absolutePath).rotate()
@@ -558,7 +558,7 @@ async function base64(arg) {
 }
 
 async function fluid({ file, args = {}, reporter, cache }) {
-  const options = healOptions(args, {})
+  const options = healOptions(pluginOptions, args, {})
   // Account for images with a high pixel density. We assume that these types of
   // images are intended to be displayed at their native resolution.
   let metadata
@@ -733,7 +733,7 @@ async function fluid({ file, args = {}, reporter, cache }) {
 }
 
 async function fixed({ file, args = {}, reporter, cache }) {
-  const options = healOptions(args, {})
+  const options = healOptions(pluginOptions, args, {})
 
   // if no width is passed, we need to resize the image based on the passed height
   const fixedDimension = options.width === undefined ? `height` : `width`
@@ -843,7 +843,7 @@ async function notMemoizedtraceSVG({ file, args, fileArgs, reporter }) {
     turnPolicy: potrace.Potrace.TURNPOLICY_MAJORITY,
   }
   const optionsSVG = _.defaults(args, defaultArgs)
-  const options = healOptions(fileArgs, {})
+  const options = healOptions(pluginOptions, fileArgs, {})
   let pipeline
   try {
     pipeline = sharp(file.absolutePath).rotate()

packages/gatsby-transformer-sharp/src/extend-node-type.js

@@ -137,7 +137,6 @@ const fixedNodeType = ({
       },
       quality: {
         type: GraphQLInt,
-        defaultValue: 50,
       },
       toFormat: {
         type: ImageFormatType,
@@ -263,7 +262,6 @@ const fluidNodeType = ({
       },
       quality: {
         type: GraphQLInt,
-        defaultValue: 50,
       },
       toFormat: {
         type: ImageFormatType,
@@ -413,7 +411,6 @@ module.exports = ({
         },
         quality: {
           type: GraphQLInt,
-          defaultValue: 50,
         },
         jpegProgressive: {
           type: GraphQLBoolean,