Universal CSN

lib/compile/unfold/assocs.js

@@ -0,0 +1,10 @@
+module.exports = (d) => {
+  if (d.kind === 'element' && !d.on && d.keys) {
+    // return console.log ('unfold assoc:', d.parent.name, d.name)
+    // Managed Associations become unmanaged ones
+    d.on = d.keys.reduce((on,k) => {
+      return on.concat([ {ref:[ d.name, ...k.ref ]}, '=', {ref:[ k.as||k.ref[0] ]} ])
+    }, [])
+    Object.defineProperty (d, 'keys', {value:d.keys, configurable:true, enumerable:false})
+  }
+}

lib/compile/unfold/index.js

@@ -0,0 +1,21 @@
+// https://github.tools.sap/cap/sflight-ea/blob/main/doc/CSN.md
+const cds = require ('@sap/cds/lib')
+
+class Unfolds {
+  get structs() { return super.structs = require('./structs.js') }
+  get assocs() { return super.assocs = require('./assocs') }
+}
+
+/**
+ * Use this function to unfold compact CSN models like that:
+ * @example cds.unfold(m,'assocs','structs')
+ * @type Unfolds & <T>(csn:T,unfolds[]:string) => T
+ */
+const unfold = Object.setPrototypeOf((csn,...unfolds)=>{
+  const done = (csn.meta ??= {}).unfolded ??= []
+  const todo = unfolds.filter(u => !done.includes(u))
+  try { return cds.linked(csn).forall(d => todo.forEach(t => unfold[t](d))) }
+  finally { done.push(...todo) }
+}, new Unfolds)
+
+module.exports = unfold

lib/compile/unfold/structs.js

@@ -0,0 +1,43 @@
+module.exports = (d) => {
+  if (d.kind === 'element' && (d.elements || d.foreignKeys)) {
+    // return console.log ('unfold struct', d.parent.name, d.name)
+    // add flattened elements for structs
+    for (let e in d.elements) {
+      let name = d.name+'_'+e
+      let flat = d.parent.elements[name] = {
+        __proto__: d.elements[e], key: d.key,
+        ... d.elements[e] // REVISIT: remove that for productive code
+      }
+      _add_derived (flat,'name',name)
+    }
+    // structs stay in model, bot become non-enumerable elements
+    if (!d.isAssociation) _add_derived (d.parent.elements, d.name, d)
+    // the flattended elements became keys -> structs associations aren't
+    delete d.key
+    // console.log (d.parent.name, d.name, d)
+  }
+}
+
+const _add_derived = (o,p,v,enumerable=false) => {
+  Object.defineProperty (o,p, { value:v, enumerable, writable:true, configurable:true })
+  return v
+}
+
+;()=>{
+
+  let payload1 ={
+    struct_a: 6,
+    struct_b: 6
+  }
+
+  let payload2 ={
+    struct: { a: 6, b: 6 }
+  }
+
+  let payload3 ={
+    struct: { a: 6, b: 6 },
+    struct_a: 7,
+    struct_b: 8
+  }
+
+}

lib/monkey-patch-cds.js

@@ -0,0 +1,15 @@
+const cds = require("@sap/cds/lib")
+
+const unfold = require("./compile/unfold")
+cds.compile.for.nodejs
+cds.compile.for.nodejs = csn => {
+  _plain_csn ??= cds.compile(cds.clone(csn))
+  return unfold(csn,'assocs','structs')
+}
+
+const _2edm = cds.compile.to.edm
+const _2sql = cds.compile.to.sql
+cds.compile.to.edm = (csn,o) => _2edm(_plain_csn||csn,o)
+cds.compile.to.sql = (csn,o) => _2sql(_plain_csn||csn,o)
+
+let _plain_csn

server.js

@@ -0,0 +1 @@
+require('./lib/monkey-patch-cds.js')