Add simple js expression model

Author: bkeepers

lib/constant.js

@@ -0,0 +1,12 @@
+// Public: A constant value like a "string", number (1, 3.5), or boolean (true, false).
+//
+// Implements the same interface as Expression
+export class Constant {
+  constructor (value) {
+    this.value = value
+  }
+
+  get args () {
+    return [this.value]
+  }
+}

lib/explorer.js

@@ -1,3 +1,4 @@
+import schemas, { BaseURI } from '../schemas'
 import pointer from 'json-pointer'
 
 export class Explorer {
@@ -40,3 +41,5 @@ export class Explorer {
     return this.get('#/definitions/function/properties')
   }
 }
+
+export default new Explorer(schemas, BaseURI)

lib/expression.js

@@ -0,0 +1,37 @@
+import { v4 as uuidv4 } from 'uuid'
+import { Constant } from './constant'
+import explorer from './explorer'
+
+// Simple model to transform this: `{ All: [{ Boolean: [true] }]`
+// into this: `{ id: uuidv4(), name: 'All', args: [{ id: uuidv4(), name: 'Boolean', args: [true] }] }`
+export class Expression {
+  static build (expression) {
+    if (expression instanceof Expression || expression instanceof Constant) {
+      return expression
+    }
+
+    if (typeof expression === 'object') {
+      const name = Object.keys(expression)[0]
+      const args = expression[name].map(Expression.build)
+      return new Expression({ name, args })
+    } else {
+      return new Constant(expression)
+    }
+  }
+
+  constructor ({ name, args, id = uuidv4() }) {
+    Object.assign(this, { name, args, id })
+  }
+
+  clone ({ id = this.id, name = this.name, args = this.args } = {}) {
+    return new Expression({ id, name, args: args.map(Expression.build) })
+  }
+
+  get value () {
+    return { [this.name]: this.args.map(arg => arg.value) }
+  }
+
+  get schema () {
+    return explorer.functions[this.name]
+  }
+}

lib/index.js

@@ -1,7 +1,6 @@
-import schemas, { BaseURI } from '../schemas'
-import { Explorer } from './explorer'
-
-export const explorer = new Explorer(schemas, BaseURI)
-export { schemas }
+export { default as schemas, BaseURI } from '../schemas'
 export { default as examples } from '../examples'
+export { default as explorer } from './explorer'
 export { default as validate } from './validate'
+export { Expression } from './expression'
+export { Constant } from './constant'

package.json

@@ -21,7 +21,8 @@
   "dependencies": {
     "ajv": "^8.12.0",
     "ajv-formats": "^2.1.1",
-    "json-pointer": "^0.6.2"
+    "json-pointer": "^0.6.2",
+    "uuid": "^9.0.0"
   },
   "devDependencies": {
     "standard": "^17.0.0",

test/expression.test.js

@@ -0,0 +1,32 @@
+import { describe, test, expect } from 'vitest'
+import { Expression, Constant } from '../lib'
+
+describe('Expression', () => {
+  describe('build', () => {
+    test('builds an expression from an object', () => {
+      const expression = Expression.build({ All: [true] })
+      expect(expression.name).toEqual('All')
+      expect(expression.args[0]).toBeInstanceOf(Constant)
+      expect(expression.args[0].value).toEqual(true)
+      expect(expression.value).toEqual({ All: [true] })
+    })
+  })
+
+  describe('clone', () => {
+    test('returns new expression', () => {
+      const expression = Expression.build({ All: [true] })
+      const clone = expression.clone()
+      expect(clone).not.toBe(expression)
+      expect(clone.name).toEqual(expression.name)
+      expect(clone.args).toEqual(expression.args)
+      expect(clone.id).toEqual(expression.id)
+    })
+
+    test('builds args', () => {
+      const expression = Expression.build({ All: [] })
+      const clone = expression.clone({ args: [true] })
+      expect(clone.args[0]).toBeInstanceOf(Constant)
+      expect(clone.value).toEqual({ All: [true] })
+    })
+  })
+})

yarn.lock

@@ -2005,6 +2005,11 @@ uri-js@^4.2.2:
   dependencies:
     punycode "^2.1.0"
 
+uuid@^9.0.0:
+  version "9.0.0"
+  resolved "https://registry.yarnpkg.com/uuid/-/uuid-9.0.0.tgz#592f550650024a38ceb0c562f2f6aa435761efb5"
+  integrity sha512-MXcSTerfPa4uqyzStbRoTgt5XIe3x5+42+q1sDuy3R5MDk66URdLMOZe5aPX/SQd+kuYAh0FdP/pO28IkQyTeg==
+
 [email protected]:
   version "0.29.8"
   resolved "https://registry.yarnpkg.com/vite-node/-/vite-node-0.29.8.tgz#6a1c9d4fb31e7b4e0f825d3a37abe3404e52bd8e"