Allow preserving BLOCK entity layers during denormalisation

src/Helper.js

@@ -6,13 +6,14 @@ import toPolylines from './toPolylines'
 import groupEntitiesByLayer from './groupEntitiesByLayer'
 
 export default class Helper {
-  constructor(contents) {
+  constructor(contents, options = {}) {
     if (!(typeof contents === 'string')) {
       throw Error('Helper constructor expects a DXF string')
     }
     this._contents = contents
     this._parsed = null
     this._denormalised = null
+    this._options = options
   }
 
   parse() {
@@ -28,8 +29,9 @@ export default class Helper {
     return this._parsed
   }
 
-  denormalise() {
-    this._denormalised = denormalise(this.parsed)
+  denormalise(options = this._options) {
+    this._denormalised = denormalise(this.parsed, options)
+    this._groups = null
     logger.info('denormalised:', this._denormalised)
     return this._denormalised
   }

src/denormalise.js

@@ -2,7 +2,26 @@ import cloneDeep from 'lodash/cloneDeep'
 
 import logger from './util/logger'
 
-export default (parseResult) => {
+const DEFAULT_LAYER = '0'
+
+const resolveInsertedEntityLayer = (
+  entityLayer,
+  insertLayer,
+  preserveBlockEntityLayers,
+) => {
+  if (!preserveBlockEntityLayers) {
+    return insertLayer
+  }
+
+  const layer = entityLayer ?? DEFAULT_LAYER
+  const resolvedInsertLayer = insertLayer ?? DEFAULT_LAYER
+
+  return layer === DEFAULT_LAYER ? resolvedInsertLayer : layer
+}
+
+export default (parseResult, options = {}) => {
+  const { preserveBlockEntityLayers = false } = options
+
   const blocksByName = parseResult.blocks.reduce((acc, b) => {
     acc[b.name] = b
     return acc
@@ -59,7 +78,11 @@ export default (parseResult) => {
             // Use the insert layer
             const blockEntities = block.entities.map((be) => {
               const be2 = cloneDeep(be)
-              be2.layer = insert.layer
+              be2.layer = resolveInsertedEntityLayer(
+                be2.layer,
+                insert.layer,
+                preserveBlockEntityLayers,
+              )
               // https://github.com/bjnortier/dxf/issues/52
               // See Issue 52. If we don't modify the
               // entity coordinates here it creates an issue with the

test/unit/denormalise.test.js

@@ -112,4 +112,107 @@ describe('Denormalise', () => {
       rotation: 120,
     })
   })
+
+  it('uses the insert layer by default', () => {
+    const parsed = {
+      blocks: [
+        {
+          name: 'DESK',
+          x: 0,
+          y: 0,
+          entities: [
+            {
+              type: 'LINE',
+              layer: 'DESK_A',
+              start: { x: 0, y: 0 },
+              end: { x: 10, y: 0 },
+            },
+          ],
+        },
+      ],
+      entities: [
+        {
+          type: 'INSERT',
+          block: 'DESK',
+          layer: 'FURNITURE',
+          x: 100,
+          y: 200,
+        },
+      ],
+    }
+
+    const entities = denormalise(parsed)
+
+    expect(entities[0].layer).toEqual('FURNITURE')
+  })
+
+  it('preserves explicit block entity layers when preserveBlockEntityLayers is true', () => {
+    const parsed = {
+      blocks: [
+        {
+          name: 'DESK',
+          x: 0,
+          y: 0,
+          entities: [
+            {
+              type: 'LINE',
+              layer: 'DESK_A',
+              start: { x: 0, y: 0 },
+              end: { x: 10, y: 0 },
+            },
+          ],
+        },
+      ],
+      entities: [
+        {
+          type: 'INSERT',
+          block: 'DESK',
+          layer: 'FURNITURE',
+          x: 100,
+          y: 200,
+        },
+      ],
+    }
+
+    const entities = denormalise(parsed, {
+      preserveBlockEntityLayers: true,
+    })
+
+    expect(entities[0].layer).toEqual('DESK_A')
+  })
+
+  it('uses the insert layer for layer 0 block entities when preserving block layers', () => {
+    const parsed = {
+      blocks: [
+        {
+          name: 'DESK',
+          x: 0,
+          y: 0,
+          entities: [
+            {
+              type: 'LINE',
+              layer: '0',
+              start: { x: 0, y: 0 },
+              end: { x: 10, y: 0 },
+            },
+          ],
+        },
+      ],
+      entities: [
+        {
+          type: 'INSERT',
+          block: 'DESK',
+          layer: 'FURNITURE',
+          x: 100,
+          y: 200,
+        },
+      ],
+    }
+
+    const entities = denormalise(parsed, {
+      preserveBlockEntityLayers: true,
+    })
+
+    expect(entities[0].layer).toEqual('FURNITURE')
+  })
 })