Fix: avoid to generate the same key for two different imported svg (#824)

* Fix: avoid to generate the same key for two different imported svg
* fix linter issues

Co-authored-by: Cédric Godefroy <cedric.godefroy@flexybeauty.com>
Co-authored-by: JFH <20402845+jfhenon@users.noreply.github.com>

src/svgcanvas/svg-exec.js

@@ -17,11 +17,11 @@ import {
   preventClickDefault,
   toXml,
   getStrokedBBoxDefaultVisible,
-  encode64,
   createObjectURL,
   dataURLToObjectURL,
   walkTree,
-  getBBox as utilsGetBBox
+  getBBox as utilsGetBBox,
+  hashCode
 } from './utilities.js'
 import { transformPoint, transformListToTransform } from './math.js'
 import { convertUnit, shortFloat, convertToNum } from '../common/units.js'
@@ -633,7 +633,7 @@ const importSvgString = (xmlString) => {
   let useEl
   try {
     // Get unique ID
-    const uid = encode64(xmlString.length + xmlString).substr(0, 32)
+    const uid = hashCode(xmlString)
 
     let useExisting = false
     // Look for symbol and make sure symbol exists in image

src/svgcanvas/utilities.js

@@ -144,6 +144,23 @@ export function decode64 (input) {
   return decodeUTF8(window.atob(input))
 }
 
+/**
+ * Compute a hashcode from a given string
+ * @param word : the string, we want to compute the hashcode
+ * @returns {number}: Hascode of the given string
+ */
+export function hashCode (word) {
+  let hash = 0
+  let chr
+  if (word.length === 0) return hash
+  for (let i = 0; i < word.length; i++) {
+    chr = word.charCodeAt(i)
+    hash = ((hash << 5) - hash) + chr
+    hash |= 0 // Convert to 32bit integer
+  }
+  return hash
+}
+
 /**
 * @function module:utilities.decodeUTF8
 * @param {string} argString