var sketch = context.api()

var document = sketch.selectedDocument;

var selection = document.selectedLayers;

var command = context.command;

var selectedLayer = context.document.selectedLayers().firstLayer()

command.setValue_forKey_onLayer_forPluginIdentifier('chips!',

'testAgain',selectedLayer,'myplugin');

log(command.valueForKey_onLayer_forPluginIdentifier('testAgain',

selectedLayer,'myplugin'));
//https://sketchplugins.com/d/41-saving-data-in-a-document

// [0] represents first override, replace with appropriate index if other override is desired

symbolInstance.setValue_forOverridePoint("New text", symbolInstance.overridePoints()[0]);
//https://gist.github.com/sonburn/f16f61cc97f50db1fc2f7172fa218b10

var value = nil,

    key = "kModelPropertiesKey",

    layer = context.selection[0],

    plugin = "com.animaapp.stc-sketch-plugin";

// Get the value

context.command.valueForKey_onLayer_forPluginIdentifier(key,layer,plugin);

// Set the value

context.command.setValue_forKey_onLayer_forPluginIdentifier(value,key,layer,plugin);

//https://gist.github.com/sonburn/71e05c03ac02cfe10fea5042215dfacd

////////////////////

var layer = context.selection[0]

context.command.setValue_forKey_onLayer("foo", "bar", layer)

log(context.command.valueForKey_onLayer("bar", layer)) // logs 'foo'

//https://sketchplugins.com/d/93-unique-id-or-tag-to-identify-component-symbol

// Set value on document

context.command.setValue_forKey_onDocument_forPluginIdentifier( 1, "testKey", context.document.documentData(), "myPluginID" );

// Get value on document

var val = context.command.valueForKey_onDocument_forPluginIdentifier( "testKey", context.document.documentData(), "myPluginID" );

log(val);

//https://sketchplugins.com/d/18-msplugincommand

////////////////////

var layer = context.selection[0]

var path = "21A3FCD7-83C0-4601-8527-67AC81E99828.2AB56A50-4051-418D-8301-DC0A3A0ADB3C.6F98D4B3-0947-4C35-85CF-0214A7DC6F4A"

log(layer.overrides().allValues().objectAtIndex(0).valueForKeyPath(path))

//https://sketchplugins.com/d/97-nested-overrides-get-value-at-key/3

symbolInstance.addOverrides_forCellAtIndex_ancestorIDs_(

{"63BC953E-4D77-4F07-B82E-6C9672330B49" : "overrideText"}, 0, nil);

///////////////////

// get the existing overrides and create a mutable copy of the parts we are interested in changing

var existingOverrides = symbolInstance.overrides();

var mutableOverrides = NSMutableDictionary.dictionaryWithDictionary(existingOverrides)

mutableOverrides.setObject_forKey(NSMutableDictionary.dictionaryWithDictionary(existingOverrides.objectForKey(0)),0)

// update the mutable dictionary

mutableOverrides.objectForKey(0).setObject_forKey("newText","63BC953E-4D77-4F07-B82E-6C9672330B49")

// apply the overrides to the symbol instance

symbolInstance.applyOverrides_allSymbols_(mutableOverrides,false);

////////////////////

var imageData = NSImage.alloc().initWithData( getImage(imgURL) );

mutableOverrides.objectForKey(0).setObject_forKey(imageData,layerIDs.artwork_ID);

////////////////////

// we need an MSImageData - let's create one from a base64 PNG

var strEncodeData = "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"

var data = NSData.alloc().initWithBase64EncodedString_options_(strEncodeData,NSDataBase64DecodingIgnoreUnknownCharacters);

var picture = NSImage.alloc().initWithData_(data);

var imageData = MSImageData.alloc().initWithImage_convertColorSpace_(picture, nil);

// get the selected layer as the symbolInstance

var symbolInstance = context.selection.firstObject();

var existingOverrides = symbolInstance.overrides();

// turn the overrides mutable

var mutableOverrides = NSMutableDictionary.dictionaryWithDictionary(existingOverrides);

// get the first one

var firstOverride = NSMutableDictionary.dictionaryWithDictionary(existingOverrides.objectForKey(0));

// set the first override to the imageData

var overrideId = [firstOverride allKeys][0];

firstOverride.setObject_forKey(imageData,overrideId)

// update the mutableOverrides

mutableOverrides.setObject_forKey(firstOverride,0);

// set the new overrides on the symbolInstance

symbolInstance.applyOverrides_allSymbols_(mutableOverrides,false);

//////////////////

// sectionDetailContent is an array with info

function executePopulateSymbol(instace, index) {

    var layerIDs = getLayerIDs(instance);

    var values = instance.overrides();

    if (!values){

        values = NSMutableDictionary.dictionary();

    }

    var existingOverrides = values;

    var mutableOverrides = NSMutableDictionary.dictionaryWithDictionary(existingOverrides)

    mutableOverrides.setObject_forKey(NSMutableDictionary.dictionaryWithDictionary(existingOverrides.objectForKey(0)),0)

    var imgURL = server + sectionDetailContent[index].thumb + "?" +token;

    var picture = NSImage.alloc().initWithData_( getImage(imgURL) );

    var imageData = MSImageData.alloc().initWithImage_convertColorSpace_(picture, nil);

    mutableOverrides.objectForKey(0).setObject_forKey(sectionDetailContent[index].title,layerIDs.title_ID)

    mutableOverrides.objectForKey(0).setObject_forKey(sectionDetailContent[index].year.toString(),layerIDs.year_ID)

    mutableOverrides.objectForKey(0).setObject_forKey(imageData,layerIDs.artwork_ID);

    instance.applyOverrides_allSymbols_(mutableOverrides,false);

}

function getLayerIDs(instance){

    var symbolMaster = instance.symbolMaster();

    var children = symbolMaster.children();

    var layerIDs = {};

    for (var i = 0; i < [children count]; i++){

        var layer = children[i];

        if( layer.name() == "Title" )   { layerIDs.title_ID   = layer.objectID() }

        if( layer.name() == "Year" )    { layerIDs.year_ID    = layer.objectID() }

        if( layer.name() == "Artwork" ) { layerIDs.artwork_ID = layer.objectID() }

    }

    return layerIDs;

}

//////////////////////////

symbolInstance.overrides = overrideObject`

const overrides = {

  exampleStringOverride: '<some-override-string-value>',

  exampleSymbolOverride: '<some-override-symbol-name-string>'

}

setOverrides(symbolInstance, overrides)

const createMain = () => ({

  symbolMasterMap: {},

  createSymbolMasterMap () {

    let symbolMasterArray = context.document.documentData().allSymbols().reverse()

    this.symbolMasterMap = {}

    for (let i = 0, len = symbolMasterArray.length; i < len; i++) {

      this.symbolMasterMap[symbolMasterArray[i].name()] = symbolMasterArray[i]

    }

  },

  buildOverrideTree (symbolMaster, tree, dept) {

    const loop = symbolMaster.children().objectEnumerator()

    let layer

    while (layer = loop.nextObject()) {

      let lookNoFurther

      const objectID = layer.objectID()

      const layerName = layer.name()

      for (let key of Object.keys(overrides)) {

        // Setting overrides with undefined results in an unsavable

        // sketch document, not sure this solves this though

        if (!key) return

        // Change this (remove`":`) to your own

        // layer override naming convention!

        if(!lookNoFurther && key + ':' == layerName) {

          const override = overrides[key]

          const overrideIsNestedSymbol = !!layer.symbolID

          if (overrideIsNestedSymbol) {

            const nestedSymbolMaster = this.symbolMasterMap[override]

            if (!nestedSymbolMaster) {

              log(`The nested Symbol override ’${override}’ is missing`)

              return false

            }

            const nestedOverrideSymbolID = nestedSymbolMaster.symbolID()

            lookNoFurther = nestedSymbolMaster

            if(!tree[objectID]) tree[objectID] = {}

            tree[objectID]['symbolID'] = nestedOverrideSymbolID

          } else {

            tree[objectID] = override

          }

        }

      }

      if (layer.className() == 'MSSymbolInstance') {

        dept++

        const subSearch = this.buildOverrideTree(lookNoFurther || layer.symbolMaster(), {}, dept)

        if(Object.keys(subSearch).length) {

          if(tree[objectID]) {

            Object.assign(tree[objectID], subSearch)

          } else {

            tree[objectID] = subSearch

          }

        }

      }

    }

    return tree

  },

  setOverrides (symbolInstance, overrides) {

    const symbolMaster = symbolInstance.symbolMaster()

    const overrideTree = this.buildOverrideTree(symbolMaster, {}, 0)

    symbolInstance.overrides = overrideTree

  }

})

// To quickly try this:

// Create 3 symbols

// Add an instance of the 2nd symbol to the 1st symbol

// Replace `exampleNestedOverrideName` with the name of the nested symbol layer

// Replace `ExampleNestedSymbol3` with the name of the 3rd symbol

// Select an instance of the 1st symbol

// Run this code from the `RunScript` panel in Sketch.

// Note that this also works when `exampleNestedOverrideName` is in some deeper nested symbol, but beware of duplicate override layer names.

const symbolInstanceLayer = context.document.selectedLayers().layers().firstObject()

const overrides = {

  exampleNestedOverrideName: 'ExampleNestedSymbol3'

}

const main = createMain()

main.createSymbolMasterMap()

main.setOverrides(symbolInstanceLayer, overrides)

//https://sketchplugins.com/d/20-how-do-i-write-to-a-symbol-instance-override/20

if ( layerType == 'MSTextLayer' ) {
    var copiedText = layer.stringValue() + "\n";
    arr.push({'x': varX, 'y': varY, 'text': copiedText});
   }

//https://github.com/explorador/sketch-copy-text-only/blob/master/CopyTextOnly.sketchplugin/Contents/Sketch/script.cocoascript