Add option preserveReferences

README.md

@@ -271,6 +271,9 @@ Convert a value to an [ESTree](https://github.com/estree/estree) node.
 
 - `instanceAsObject` (boolean, default: `false`) — If true, treat objects that have a prototype as
   plain objects.
+- `preserveReferences` (boolean, default: `false`) — If true, preserve references to the same object
+  found within the input. This also allows to serialize recursive structures. If needed, the
+  resulting expression will be an iife.
 
 ## Compatibility
 

fixtures/array-multi-reference/input.js

@@ -0,0 +1,20 @@
+// Used as input
+// { preserveReferences: true }
+export default (() => {
+  const $0 = new Date(3)
+  return [1, 'Hello', null, new Date(1), new Date(2), $0, $0]
+})()
+
+// -------------------------------------------------------------------------------------------------
+
+// Default output
+// { preserveReferences: false }
+const withoutPreserveReferences = [
+  1,
+  'Hello',
+  null,
+  new Date(1),
+  new Date(2),
+  new Date(3),
+  new Date(3)
+]

fixtures/array-recursive-nested-deep/input.js

@@ -0,0 +1,13 @@
+// Used as input
+// { preserveReferences: true }
+export default (() => {
+  const $1 = ['variable 1', , ,],
+    $0 = ['variable 0', ['variable 2', $1]]
+  return ($1[1] = $0)
+})()
+
+// -------------------------------------------------------------------------------------------------
+
+// Default output
+// { preserveReferences: false }
+// Recursive references are not supported witout preserveReferences

fixtures/array-recursive-nested/input.js

@@ -0,0 +1,13 @@
+// Used as input
+// { preserveReferences: true }
+export default (() => {
+  const $1 = ['variable 1', ,],
+    $0 = ['variable 0', $1]
+  return ($1[1] = $0)
+})()
+
+// -------------------------------------------------------------------------------------------------
+
+// Default output
+// { preserveReferences: false }
+// Recursive references are not supported witout preserveReferences

fixtures/array-recursive/input.js

@@ -0,0 +1,12 @@
+// Used as input
+// { preserveReferences: true }
+export default (() => {
+  const $0 = ['recursive', , ,]
+  return ($0[1] = $0)
+})()
+
+// -------------------------------------------------------------------------------------------------
+
+// Default output
+// { preserveReferences: false }
+// Recursive references are not supported witout preserveReferences

fixtures/array/input.js

@@ -1 +1,9 @@
-export default [1, '2', , undefined]
+// Used as input
+// { preserveReferences: true }
+export default [1, '2', , {}, ,]
+
+// -------------------------------------------------------------------------------------------------
+
+// Default output
+// { preserveReferences: false }
+const withoutPreserveReferences = [1, '2', , {}, ,]

fixtures/big-int/input.js

@@ -1 +1,9 @@
+// Used as input
+// { preserveReferences: true }
 export default 1337n
+
+// -------------------------------------------------------------------------------------------------
+
+// Default output
+// { preserveReferences: false }
+const withoutPreserveReferences = 1337n

fixtures/big-int64array/input.js

@@ -1 +1,9 @@
+// Used as input
+// { preserveReferences: true }
 export default new BigInt64Array([1n, 2n, 3n])
+
+// -------------------------------------------------------------------------------------------------
+
+// Default output
+// { preserveReferences: false }
+const withoutPreserveReferences = new BigInt64Array([1n, 2n, 3n])

fixtures/big-uint64array/input.js

@@ -1 +1,9 @@
+// Used as input
+// { preserveReferences: true }
 export default new BigUint64Array([1n, 2n, 3n])
+
+// -------------------------------------------------------------------------------------------------
+
+// Default output
+// { preserveReferences: false }
+const withoutPreserveReferences = new BigUint64Array([1n, 2n, 3n])

fixtures/buffer/input.js

@@ -1 +1,9 @@
+// Used as input
+// { preserveReferences: true }
 export default Buffer.from([1, 2, 3])
+
+// -------------------------------------------------------------------------------------------------
+
+// Default output
+// { preserveReferences: false }
+const withoutPreserveReferences = Buffer.from([1, 2, 3])

fixtures/date/input.js

@@ -1 +1,9 @@
+// Used as input
+// { preserveReferences: true }
 export default new Date(1234567890123)
+
+// -------------------------------------------------------------------------------------------------
+
+// Default output
+// { preserveReferences: false }
+const withoutPreserveReferences = new Date(1234567890123)

fixtures/false-object/input.js

@@ -1 +1,9 @@
+// Used as input
+// { preserveReferences: true }
 export default new Boolean(false)
+
+// -------------------------------------------------------------------------------------------------
+
+// Default output
+// { preserveReferences: false }
+const withoutPreserveReferences = new Boolean(false)

fixtures/false/input.js

@@ -1 +1,9 @@
+// Used as input
+// { preserveReferences: true }
 export default false
+
+// -------------------------------------------------------------------------------------------------
+
+// Default output
+// { preserveReferences: false }
+const withoutPreserveReferences = false

fixtures/float32array/input.js

@@ -1 +1,9 @@
+// Used as input
+// { preserveReferences: true }
 export default new Float32Array([1, 2, 3])
+
+// -------------------------------------------------------------------------------------------------
+
+// Default output
+// { preserveReferences: false }
+const withoutPreserveReferences = new Float32Array([1, 2, 3])

fixtures/float64array/input.js

@@ -1 +1,9 @@
+// Used as input
+// { preserveReferences: true }
 export default new Float64Array([1, 2, 3])
+
+// -------------------------------------------------------------------------------------------------
+
+// Default output
+// { preserveReferences: false }
+const withoutPreserveReferences = new Float64Array([1, 2, 3])

fixtures/infinity/input.js

@@ -1 +1,9 @@
+// Used as input
+// { preserveReferences: true }
 export default Infinity
+
+// -------------------------------------------------------------------------------------------------
+
+// Default output
+// { preserveReferences: false }
+const withoutPreserveReferences = Infinity

fixtures/int16array/input.js

@@ -1 +1,9 @@
+// Used as input
+// { preserveReferences: true }
 export default new Int16Array([1, 2, 3])
+
+// -------------------------------------------------------------------------------------------------
+
+// Default output
+// { preserveReferences: false }
+const withoutPreserveReferences = new Int16Array([1, 2, 3])

fixtures/int32array/input.js

@@ -1 +1,9 @@
+// Used as input
+// { preserveReferences: true }
 export default new Int32Array([1, 2, 3])
+
+// -------------------------------------------------------------------------------------------------
+
+// Default output
+// { preserveReferences: false }
+const withoutPreserveReferences = new Int32Array([1, 2, 3])

fixtures/int8array/input.js

@@ -1 +1,9 @@
+// Used as input
+// { preserveReferences: true }
 export default new Int8Array([1, 2, 3])
+
+// -------------------------------------------------------------------------------------------------
+
+// Default output
+// { preserveReferences: false }
+const withoutPreserveReferences = new Int8Array([1, 2, 3])

fixtures/map-multi-reference/input.js

@@ -0,0 +1,25 @@
+// Used as input
+// { preserveReferences: true }
+export default (() => {
+  const $0 = {},
+    $1 = {}
+  return new Map([
+    ['key', {}],
+    [{}, 'value'],
+    [$0, 42],
+    [42, $0],
+    [$1, $1]
+  ])
+})()
+
+// -------------------------------------------------------------------------------------------------
+
+// Default output
+// { preserveReferences: false }
+const withoutPreserveReferences = new Map([
+  ['key', {}],
+  [{}, 'value'],
+  [{}, 42],
+  [42, {}],
+  [{}, {}]
+])

fixtures/map-recursive-deep/input.js

@@ -0,0 +1,18 @@
+// Used as input
+// { preserveReferences: true }
+export default (() => {
+  const $1 = new Map(),
+    $2 = new Map(),
+    $0 = new Map([
+      ['recursive', 'value'],
+      ['key', $1],
+      [$2, 'value']
+    ])
+  return $1.set('key', $0), $2.set($0, 'value'), $0
+})()
+
+// -------------------------------------------------------------------------------------------------
+
+// Default output
+// { preserveReferences: false }
+// Recursive references are not supported witout preserveReferences

fixtures/map-recursive/input.js

@@ -0,0 +1,12 @@
+// Used as input
+// { preserveReferences: true }
+export default (() => {
+  const $0 = new Map([['recursive', 'value']])
+  return $0.set('key', $0).set($0, 'value')
+})()
+
+// -------------------------------------------------------------------------------------------------
+
+// Default output
+// { preserveReferences: false }
+// Recursive references are not supported witout preserveReferences

fixtures/map/input.js

@@ -1,4 +1,15 @@
+// Used as input
+// { preserveReferences: true }
 export default new Map([
   [{}, 42],
   [42, {}]
 ])
+
+// -------------------------------------------------------------------------------------------------
+
+// Default output
+// { preserveReferences: false }
+const withoutPreserveReferences = new Map([
+  [{}, 42],
+  [42, {}]
+])

fixtures/nan/input.js

@@ -1 +1,9 @@
+// Used as input
+// { preserveReferences: true }
 export default NaN
+
+// -------------------------------------------------------------------------------------------------
+
+// Default output
+// { preserveReferences: false }
+const withoutPreserveReferences = NaN

fixtures/negative-bigint/input.js

@@ -1 +1,9 @@
+// Used as input
+// { preserveReferences: true }
 export default -7n
+
+// -------------------------------------------------------------------------------------------------
+
+// Default output
+// { preserveReferences: false }
+const withoutPreserveReferences = -7n

fixtures/negative-infinity/input.js

@@ -1 +1,9 @@
+// Used as input
+// { preserveReferences: true }
 export default -Infinity
+
+// -------------------------------------------------------------------------------------------------
+
+// Default output
+// { preserveReferences: false }
+const withoutPreserveReferences = -Infinity

fixtures/negative-number-object/input.js

@@ -1 +1,9 @@
+// Used as input
+// { preserveReferences: true }
 export default new Number(-456)
+
+// -------------------------------------------------------------------------------------------------
+
+// Default output
+// { preserveReferences: false }
+const withoutPreserveReferences = new Number(-456)

fixtures/negative-number/input.js

@@ -1 +1,9 @@
+// Used as input
+// { preserveReferences: true }
 export default -37
+
+// -------------------------------------------------------------------------------------------------
+
+// Default output
+// { preserveReferences: false }
+const withoutPreserveReferences = -37

fixtures/negative-zero/input.js

@@ -1 +1,9 @@
+// Used as input
+// { preserveReferences: true }
 export default -0
+
+// -------------------------------------------------------------------------------------------------
+
+// Default output
+// { preserveReferences: false }
+const withoutPreserveReferences = -0

fixtures/null/input.js

@@ -1 +1,9 @@
+// Used as input
+// { preserveReferences: true }
 export default null
+
+// -------------------------------------------------------------------------------------------------
+
+// Default output
+// { preserveReferences: false }
+const withoutPreserveReferences = null

fixtures/number-object/input.js

@@ -1 +1,9 @@
+// Used as input
+// { preserveReferences: true }
 export default new Number(123)
+
+// -------------------------------------------------------------------------------------------------
+
+// Default output
+// { preserveReferences: false }
+const withoutPreserveReferences = new Number(123)

fixtures/number/input.js

@@ -1 +1,9 @@
+// Used as input
+// { preserveReferences: true }
 export default 42
+
+// -------------------------------------------------------------------------------------------------
+
+// Default output
+// { preserveReferences: false }
+const withoutPreserveReferences = 42