Started implementing constant property

app/imports/api/properties/Constants.js

@@ -0,0 +1,35 @@
+import SimpleSchema from 'simpl-schema';
+import VARIABLE_NAME_REGEX from '/imports/constants/VARIABLE_NAME_REGEX.js';
+
+/*
+ * Constants are primitive values that can be used elsewhere in computations
+ */
+let ConstantSchema = new SimpleSchema({
+  name: {
+		type: String,
+		optional: true,
+	},
+  // The technical, lowercase, single-word name used in formulae
+  variableName: {
+    type: String,
+		regEx: VARIABLE_NAME_REGEX,
+    min: 2,
+    defaultValue: 'newConstant',
+  },
+	// The input value to be parsed, must return a constant node or an array
+  // of constant nodes to be valid
+	calculation: {
+		type: String,
+		optional: true,
+	},
+  // The value, or array of values
+  result: {
+    type: SimpleSchema.oneOf(String, Number, Boolean, Array),
+    maxSize: 32,
+  },
+  'result.$': {
+    type: SimpleSchema.oneOf(String, Number, Boolean),
+  }
+});
+
+export { ConstantSchema };

app/imports/parser/parseTree/ArrayNode.js

@@ -1,10 +1,27 @@
 import ParseNode from '/imports/parser/parseTree/ParseNode.js';
+import ConstantNode from '/imports/parser/parseTree/ConstantNode.js';
 
 export default class ArrayNode extends ParseNode {
   constructor({values}) {
     super(...arguments);
     this.values = values;
   }
+  static fromConstantArray(array){
+    let values = array.map( value => {
+      let type = typeof value;
+      if (
+        type === 'string' ||
+        type === 'number' ||
+        type === 'boolean' ||
+        type === 'undefined'
+      ){
+        return new ConstantNode({value, type});
+      } else {
+        throw `Unexpected type in constant array: ${type}`
+      }
+    });
+    return new ArrayNode({values});
+  }
   resolve(fn, scope, context){
     let values = this.values.map(node => node[fn](scope, context));
     return new ArrayNode({values});