add support for start and end code

src/sliceActions/helpers/GCode.js

@@ -122,6 +122,15 @@ export default class {
     return this;
   }
 
+  addGCode(gcode, { temperature, bedTemperature, heatedbed }) {
+    gcode = gcode
+      .replace(/{temperature}/gi, temperature)
+      .replace(/{bedTemperature}/gi, bedTemperature)
+      .replace(/{if heatedBed}/gi, heatedbed ? '' : ';');
+
+    this._addGCode(gcode);
+  }
+
   getGCode() {
     return {
       gcode: this._gcode,

src/sliceActions/slice.js

@@ -76,6 +76,9 @@ export default function(settings, geometry, openObjectIndexes, constructLinePrev
 function gcodeToString(gcode) {
   const currentValues = {};
   return gcode.reduce((string, command) => {
+    if (typeof command === 'string') {
+      string += command;
+    } else {
       let first = true;
       for (const action in command) {
         const value = command[action];
@@ -88,6 +91,7 @@ function gcodeToString(gcode) {
           currentValues[action] = value;
         }
       }
+    }
     string += '\n';
     return string;
   }, '');
@@ -101,7 +105,10 @@ function createGcodeGeometry(gcode) {
 
   let lastPoint = [0, 0, 0];
   for (let i = 0; i < gcode.length; i ++) {
-    const { G, F, X, Y, Z } = gcode[i];
+    const command = gcode[i];
+    if (typeof command === 'string') continue;
+
+    const { G, F, X, Y, Z } = command;
 
     if (X || Y || Z) {
       if (G === 1) {

src/sliceActions/slicesToGCode.js

@@ -22,6 +22,8 @@ export default function slicesToGCode(slices, settings) {
 
   const gcode = new GCode(nozzleToFilamentRatio);
 
+  if (settings.startCode) gcode.addGCode(settings.startCode, settings);
+
   const defaultProfile = {
     travelProfile: travel,
     retractionProfile: retraction
@@ -77,6 +79,8 @@ export default function slicesToGCode(slices, settings) {
     }
   }
 
+  if (settings.endCode) gcode.addGCode(settings.endCode, settings);
+
   return gcode.getGCode();
 }