feat(core): add string template engine to evaluators (#3546)

* feat(core): add string template engine to evaluators

* refactor(plugin-workflow): simplify api

* Revert "refactor(plugin-workflow): simplify api"

This reverts commit 6ff2bb9220.

* fix(plugin-workflow): fix test case

* refactor(core): adjust variable regular expression

packages/core/client/src/locale/zh-CN.json

@@ -262,11 +262,11 @@
   "String": "字符串",
   "Password": "密码",
   "Advanced type": "高级类型",
-  "Formula": "公式",
-  "Formula description": "基于同一条记录中的其他字段计算出一个值。",
   "Syntax references": "语法参考",
-  "Math.js comes with a large set of built-in functions and constants, and offers an integrated solution to work with different data types": "Math.js 包含大量内置函数和常量，并提供了集成的解决方案来处理不同的数据类型。",
+  "Math.js comes with a large set of built-in functions and constants, and offers an integrated solution to work with different data types.": "Math.js 包含大量内置函数和常量，并提供了集成的解决方案来处理不同的数据类型。",
   "Formula.js supports most Microsoft Excel formula functions.": "Formula.js 支持大部分 Mircrosoft Excel 公式。",
+  "String template": "字符串模板",
+  "Simple string replacement, can be used to interpolate variables in a string.": "简单的字符串替换，可以用于在字符串中插入变量。",
   "Choices": "选择类型",
   "Checkbox": "勾选",
   "Display <icon></icon> when unchecked": "未勾选时显示 <icon></icon>",

packages/core/evaluators/src/client/engines/formulajs.ts

@@ -1,9 +1,8 @@
-import { evaluate } from '../../utils';
 import formulajs from '../../utils/formulajs';
 
 export default {
   label: 'Formula.js',
   tooltip: '{{t("Formula.js supports most Microsoft Excel formula functions.")}}',
   link: 'https://formulajs.info/functions/',
-  evaluate: evaluate.bind(formulajs),
+  evaluate: formulajs,
 };

packages/core/evaluators/src/client/engines/mathjs.ts

@@ -1,9 +1,8 @@
-import { evaluate } from '../../utils';
 import mathjs from '../../utils/mathjs';
 
 export default {
   label: 'Math.js',
-  tooltip: `{{t('Math.js comes with a large set of built-in functions and constants, and offers an integrated solution to work with different data types')}}`,
+  tooltip: `{{t('Math.js comes with a large set of built-in functions and constants, and offers an integrated solution to work with different data types.')}}`,
   link: 'https://mathjs.org/',
-  evaluate: evaluate.bind(mathjs),
+  evaluate: mathjs,
 };

packages/core/evaluators/src/client/engines/string.ts

@@ -0,0 +1,7 @@
+import string from '../../utils/string';
+
+export default {
+  label: `{{t('String template')}}`,
+  tooltip: `{{t('Simple string replacement, can be used to interpolate variables in a string.')}}`,
+  evaluate: string,
+};

packages/core/evaluators/src/client/index.tsx

@@ -2,6 +2,7 @@ import { Registry } from '@nocobase/utils/client';
 
 import mathjs from './engines/mathjs';
 import formulajs from './engines/formulajs';
+import string from './engines/string';
 
 export interface Evaluator {
   label: string;
@@ -14,6 +15,7 @@ export const evaluators = new Registry<Evaluator>();
 
 evaluators.register('math.js', mathjs);
 evaluators.register('formula.js', formulajs);
+evaluators.register('string', string);
 
 export function getOptions() {
   return Array.from((evaluators as Registry<Evaluator>).getEntities()).reduce(

packages/core/evaluators/src/server/__tests__/index.test.ts

@@ -1,9 +1,88 @@
+import { evaluate } from '../../utils';
 import evaluators from '..';
 
+describe('evaluate', () => {
+  describe('pre-process', () => {
+    const preProcess = evaluate.bind((expression, scope) => ({ expression, scope }), {});
+    const preProcessReplaceValue = evaluate.bind((expression, scope) => ({ expression, scope }), {
+      replaceValue: true,
+    });
+
+    it('only variable as null', () => {
+      const { expression, scope } = preProcess('{{a}}', { a: null });
+      expect(expression).toBe(`$$0`);
+      expect(scope.$$0).toBeNull();
+    });
+
+    it('string containing variable', () => {
+      const { expression, scope } = preProcess('a{{a}}b', { a: 1 });
+      expect(expression).toBe(`a$$0b`);
+      expect(scope.$$0).toBe(1);
+    });
+
+    it('duplicated variable name in expression should be unique in new scope', () => {
+      const { expression, scope } = preProcess('{{a}} {{a}}', { a: 1 });
+      expect(expression).toBe(`$$0 $$0`);
+      expect(Object.keys(scope).length).toBe(1);
+      expect(scope.$$0).toBe(1);
+    });
+
+    it('number path to array item 0', () => {
+      const { expression, scope } = preProcess('{{a.0}}', { a: [1, 2, 3] });
+      expect(expression).toBe(`$$0`);
+      expect(scope.$$0).toBe(1);
+    });
+
+    it('number path to array item 1', () => {
+      const { expression, scope } = preProcess('{{a.1}}', { a: [1, 2, 3] });
+      expect(expression).toBe(`$$0`);
+      expect(scope.$$0).toBe(2);
+    });
+
+    it('deep array path', () => {
+      const { expression, scope } = preProcess('{{a.b}}', { a: [{ b: 1 }, { b: 2 }] });
+      expect(expression).toBe(`$$0`);
+      expect(scope.$$0).toEqual([1, 2]);
+    });
+
+    it('pre-process replace value', () => {
+      const { expression, scope } = preProcessReplaceValue('a{{a}}b', { a: 1 });
+      expect(expression).toBe(`a1b`);
+      expect(scope.$$0).toBe(1);
+    });
+  });
+
+  describe('math.js', () => {
     const mathEval = evaluators.get('math.js');
+
+    it('number path to array item 0 (math.js)', () => {
+      expect(() => mathEval('{{a}}[0]', { a: [1, 2, 3] })).toThrow();
+    });
+
+    it('number path to array item 1 (math.js)', () => {
+      const result = mathEval('{{a}}[1]', { a: [1, 2, 3] });
+      expect(result).toBe(1);
+    });
+
+    it('number path to array item 0 (math.js)', () => {
+      const result = mathEval('{{a.0}}', { a: [1, 2, 3] });
+      expect(result).toBe(1);
+    });
+
+    it('number path to object member 0 (math.js)', () => {
+      const result = mathEval('{{a.1}}', { a: { 1: 1 } });
+      expect(result).toBe(1);
+    });
+
+    it('string expression with space', () => {
+      const result = mathEval('{{a}}  + 1', { a: 1 });
+      expect(result).toBe(2);
+    });
+  });
+
+  describe('formula.js', () => {
     const formulaEval = evaluators.get('formula.js');
 
-describe('evaluate', () => {
     it('reference null or undefined', () => {
       const result = formulaEval('{{a.b}}', { a: null });
       expect(result).toBeNull();
@@ -62,28 +141,57 @@ describe('evaluate', () => {
       expect(result).toBe(1);
     });
 
-  it('number path to array item 1 (math.js)', () => {
-    const result = mathEval('{{a}}[1]', { a: [1, 2, 3] });
-    expect(result).toBe(1);
-  });
-
-  // NOTE: This case is skipped because `a.<number>` is not able to be configured from UI.
-  it.skip('number path to array item 0 (math.js)', () => {
-    expect(() => mathEval('{{a.0}}', { a: [1, 2, 3] })).toThrow();
-  });
-
-  it.skip('number path to array item 1 (math.js)', () => {
-    const result = mathEval('{{a.1}}', { a: [1, 2, 3] });
-    expect(result).toBe(1);
-  });
-
-  it('number path to object member 0 (math.js)', () => {
-    const result = mathEval('{{a.1}}', { a: { 1: 1 } });
-    expect(result).toBe(1);
-  });
-
     it('number lead string path to object member (formula.js)', () => {
       const result = formulaEval('{{a.1a}}', { a: { '1a': 1 } });
       expect(result).toBe(1);
     });
   });
+
+  describe('string', () => {
+    const stringReplace = evaluators.get('string');
+
+    it('only variable', () => {
+      const result = stringReplace('{{a}}', { a: 1 });
+      expect(result).toBe('1');
+    });
+
+    it('string containing undefined variable', () => {
+      const result = stringReplace('a{{a}}b', {});
+      expect(result).toBe('ab');
+    });
+
+    it('string containing null variable', () => {
+      const result = stringReplace('a{{a}}b', { a: null });
+      expect(result).toBe('ab');
+    });
+
+    it('string containing boolean variable', () => {
+      const result = stringReplace('a{{a}}b', { a: false });
+      expect(result).toBe('afalseb');
+    });
+
+    it('string containing number variable', () => {
+      const result = stringReplace('a{{a}}b', { a: 1 });
+      expect(result).toBe('a1b');
+    });
+
+    it('string containing NaN variable', () => {
+      const result = stringReplace('a{{a}}b', { a: Number.NaN });
+      expect(result).toBe('ab');
+    });
+
+    it('string containing infinite variable', () => {
+      const result = stringReplace('a{{a}}b', { a: Number.POSITIVE_INFINITY });
+      expect(result).toBe('ab');
+    });
+
+    it('string containing function variable', () => {
+      const result = stringReplace('a{{a}}b', {
+        a() {
+          return 1;
+        },
+      });
+      expect(result).toBe('a1b');
+    });
+  });
+});

packages/core/evaluators/src/server/index.ts

@@ -1,14 +1,16 @@
 import { Registry } from '@nocobase/utils';
 
-import { evaluate, Evaluator } from '../utils';
+import { Evaluator } from '../utils';
 import mathjs from '../utils/mathjs';
 import formulajs from '../utils/formulajs';
+import string from '../utils/string';
 
 export { Evaluator, evaluate, appendArrayColumn } from '../utils';
 
 export const evaluators = new Registry<Evaluator>();
 
-evaluators.register('math.js', evaluate.bind(mathjs));
-evaluators.register('formula.js', evaluate.bind(formulajs));
+evaluators.register('math.js', mathjs);
+evaluators.register('formula.js', formulajs);
+evaluators.register('string', string);
 
 export default evaluators;

packages/core/evaluators/src/utils/formulajs.ts

@@ -1,9 +1,11 @@
 import * as functions from '@formulajs/formulajs';
 
+import { evaluate } from '.';
+
 const fnNames = Object.keys(functions).filter((key) => key !== 'default');
 const fns = fnNames.map((key) => functions[key]);
 
-export default function (expression: string, scope = {}) {
+export default evaluate.bind(function (expression: string, scope = {}) {
   const fn = new Function(...fnNames, ...Object.keys(scope), `return ${expression}`);
   const result = fn(...fns, ...Object.values(scope));
   if (typeof result === 'number') {
@@ -13,4 +15,4 @@ export default function (expression: string, scope = {}) {
     return functions.ROUND(result, 9);
   }
   return result;
-}
+}, {});

packages/core/evaluators/src/utils/index.ts

@@ -17,24 +17,34 @@ export function appendArrayColumn(scope, key) {
   }
 }
 
-export function evaluate(this: Evaluator, expression: string, scope: Scope = {}) {
+interface EvaluatorOptions {
+  replaceValue?: boolean;
+}
+
+export function evaluate(this: Evaluator, options: EvaluatorOptions = {}, expression: string, scope: Scope = {}) {
   const context = cloneDeep(scope);
   const newContext = {};
-  const exp = expression.trim().replace(/{{\s*([^{}]+)\s*}}/g, (_, v) => {
+  const keyMap = {};
+  let index = 0;
+  const exp = expression.trim().replace(/{{\s*([\w$.-]+)\s*}}/g, (_, v) => {
     appendArrayColumn(context, v);
 
-    let item = get(context, v);
+    let item = get(context, v) ?? null;
 
     if (typeof item === 'function') {
       item = item();
     }
 
-    const randomKey = `$$${Math.random().toString(36).slice(2, 10).padEnd(8, '0')}`;
-    if (item == null) {
-      return 'null';
+    let key = keyMap[v];
+    if (!key) {
+      key = `$$${index++}`;
+      keyMap[v] = key;
+
+      newContext[key] = item;
     }
-    newContext[randomKey] = item;
-    return ` ${randomKey} `;
+    return options.replaceValue
+      ? `${item == null || (typeof item === 'number' && (Number.isNaN(item) || !Number.isFinite(item))) ? '' : item}`
+      : key;
   });
 
   return this(exp, newContext);

packages/core/evaluators/src/utils/mathjs.ts

@@ -1,6 +1,9 @@
 import * as math from 'mathjs';
 
-export default function (expression: string, scope = {}) {
+import { evaluate } from '.';
+
+export default evaluate.bind(
+  function (expression: string, scope = {}) {
     const result = math.evaluate(expression, scope);
     if (typeof result === 'number') {
       if (Number.isNaN(result) || !Number.isFinite(result)) {
@@ -9,4 +12,6 @@ export default function (expression: string, scope = {}) {
       return math.round(result, 9);
     }
     return result;
-}
+  },
+  { replaceKey: true },
+);

packages/core/evaluators/src/utils/string.ts

@@ -0,0 +1,8 @@
+import { evaluate } from '.';
+
+export default evaluate.bind(
+  function (expression: string, scope = {}) {
+    return expression;
+  },
+  { replaceValue: true },
+);

packages/plugins/@nocobase/plugin-workflow/src/locale/zh-CN.json

@@ -94,8 +94,8 @@
   "Scope variables": "局域变量",
 
   "Operator": "运算符",
-  "Calculate an expression based on a calculation engine and obtain a value as the result. Variables in the upstream nodes can be used in the expression. The expression can be static or dynamic one from an expression collections.":
-    "基于计算引擎对一个表达式进行计算，并获得一个值作为结果。表达式中可以使用上游节点里的变量。表达式可以是静态的，也可以是表达式表中的动态表达式。",
+  "Calculate an expression based on a calculation engine and obtain a value as the result. Variables in the upstream nodes can be used in the expression.":
+    "基于计算引擎对一个表达式进行计算，并获得一个值作为结果。表达式中可以使用上游节点里的变量。",
   "String operation": "字符串",
   "System variables": "系统变量",
   "System time": "系统时间",

packages/plugins/@nocobase/plugin-workflow/src/server/__tests__/instructions/calculation.test.ts

@@ -166,8 +166,7 @@ describe('workflow > instructions > calculation', () => {
 
       const [execution] = await workflow.getExecutions();
       const [job] = await execution.getJobs();
-      expect((job.result as string).startsWith('a $$')).toBe(true);
-      expect((job.result as string).endsWith(' ')).toBe(true);
+      expect(job.result).toBe('a$$0');
     });
 
     it('text', async () => {