fix(core): Put getId into a closure

packages/core/src/part.mjs

@@ -77,18 +77,6 @@ Part.prototype.attr = function (name, value, overwrite = false) {
   return this
 }
 
-/**
- * Returns on unused ID (unused in this part)
- *
- * @param {string} prefix - An optional prefix to apply to the ID
- * @return {string} id - The id
- */
-Part.prototype.getId = function (prefix = '') {
-  this.freeId += 1
-
-  return prefix + this.freeId
-}
-
 /**
  * Hide the part
  *
@@ -125,7 +113,7 @@ Part.prototype.shorthand = function () {
   const shorthand = {
     complete,
     context: this.context,
-    getId: this.getId,
+    getId: this.__getIdClosure(),
     hide: this.hide,
     log: this.context.store.log,
     paperless,
@@ -289,6 +277,22 @@ Part.prototype.__boundary = function () {
   return this
 }
 
+/**
+ * Returns a closure holding a getId method (returns an ID unused in this part)
+ *
+ * @return {function} getId - The getId function
+ */
+Part.prototype.__getIdClosure = function () {
+  const self = this
+  const method = function (prefix = '') {
+    self.freeId += 1
+
+    return prefix + self.freeId
+  }
+
+  return method
+}
+
 /**
  * Copies point/path/snippet data from part orig into this
  *

packages/core/tests/part.test.mjs

@@ -58,10 +58,22 @@ describe('Part', () => {
     expect(pattern.parts[0].test.points.macro.y).to.equal(456)
   })
 
-  it('Should return a free ID', () => {
-    const part = new Part()
-    const free = part.getId()
-    expect(part.getId()).to.equal('' + (parseInt(free) + 1))
+  it('Should return a free ID in draft method', () => {
+    let id = null
+    const part = {
+      name: 'test',
+      draft: ({ getId, part }) => {
+        console.log(getId)
+        id = getId()
+        id = getId()
+        id = getId()
+
+        return part
+      },
+    }
+    const design = new Design({ parts: [part] })
+    new design().draft()
+    expect(id).to.equal('3')
   })
 
   it('Should return a function from __unitsClosure', () => {