feat: json variable access (VF-3664)

packages/common/src/constants/regexp.ts

@@ -6,7 +6,8 @@ export const SLOT_ANNOTATION_SIMPLE_REGEX = /{([^ .[\]{}]+?)}/g;
 
 export const IS_VARIABLE_REGEXP = /^{.*}$/;
 
-export const READABLE_VARIABLE_REGEXP = /{(\w{1,64})}/g;
+// export const READABLE_VARIABLE_REGEXP = /{(\w{1,64})}/g;
+export const READABLE_VARIABLE_REGEXP = /{(\w{1,64})((?:\.\w{1,64}|\[\d+])*)}/gi;
 
 export const VALID_CHARACTER = 'a-zA-Z';
 

packages/common/src/utils/variables.ts

@@ -3,14 +3,37 @@ import { READABLE_VARIABLE_REGEXP } from '@common/constants';
 export const variableReplacer = (
   match: string,
   inner: string,
+  selectors: string[],
   variables: Record<string, unknown>,
   modifier?: (variable: unknown) => unknown
 ): unknown => {
-  if (inner in variables) {
-    return typeof modifier === 'function' ? modifier(variables[inner]) : variables[inner];
+  if (!(inner in variables)) {
+    return match;
   }
 
-  return match;
+  let replaced: any = variables[inner];
+
+  let selectorString = selectors[0];
+  while (selectorString.length > 0) {
+    // eslint-disable-next-line no-loop-func
+    selectorString = selectorString.replace(/^\.(\w{1,64})/, (_m, field) => {
+      replaced = replaced[field];
+      return '';
+    });
+    if (replaced === undefined) {
+      break;
+    }
+    // eslint-disable-next-line no-loop-func
+    selectorString = selectorString.replace(/^\[(\d+)]/, (_m, index) => {
+      replaced = replaced[index];
+      return '';
+    });
+    if (replaced === undefined) {
+      break;
+    }
+  }
+
+  return typeof modifier === 'function' ? modifier(replaced) : replaced;
 };
 
 export const replaceVariables = (
@@ -23,7 +46,9 @@ export const replaceVariables = (
     return '';
   }
 
-  return phrase.replace(READABLE_VARIABLE_REGEXP, (match, inner) => String(variableReplacer(match, inner, variables, modifier)));
+  return phrase.replace(READABLE_VARIABLE_REGEXP, (match, inner, ...selectors) =>
+    String(variableReplacer(match, inner, selectors, variables, modifier))
+  );
 };
 
 // turn float variables to 2 decimal places

packages/common/tests/utils/variables.unit.ts

@@ -0,0 +1,50 @@
+import { replaceVariables } from '@common/utils/variables';
+import { expect } from 'chai';
+
+describe('Utils | variables', () => {
+  describe('replaceVariables', () => {
+    const variables = {
+      name: 'bob',
+      age: 32,
+      favFoods: ['takoyaki', 'onigiri', 'taiyaki'],
+      job: {
+        company: 'voiceflow',
+        position: 'software engineer',
+        team: 'creator',
+      },
+    };
+    it('correctly replaces simple variables', () => {
+      expect(replaceVariables('hello, my name is {name}, and i am {age} years old', variables)).to.eq('hello, my name is bob, and i am 32 years old');
+      expect(replaceVariables('{name} {name} {name}', variables)).to.eq('bob bob bob');
+    });
+    it('variables that are not defined do not get expanded', () => {
+      expect(replaceVariables('hello, my name is {name} and i work at {workplace}', variables)).to.eq(
+        'hello, my name is bob and i work at {workplace}'
+      );
+      expect(replaceVariables('hello, my name is {Name}', variables)).to.eq('hello, my name is {Name}');
+    });
+
+    it('array access works', () => {
+      expect(replaceVariables('most favorite food is {favFoods[0]}, second favorite is {favFoods[1]}, and third is {favFoods[2]}', variables)).to.eq(
+        'most favorite food is takoyaki, second favorite is onigiri, and third is taiyaki'
+      );
+    });
+    // it('index out of range', () => {});
+
+    it('object access works', () => {
+      expect(replaceVariables('i work at {job.company} as a {job.position} on the {job.team} team', variables)).to.eq(
+        'i work at voiceflow as a software engineer on the creator team'
+      );
+    });
+    // it('non-existent fields', () => {});
+
+    it('weird cases', () => {
+      const variables = {
+        '': 6969,
+        var: '{name}',
+      };
+      expect(replaceVariables('this is a blank variable {}', variables)).to.eq('this is a blank variable {}');
+      expect(replaceVariables('{var}', variables)).to.eq('{name}');
+    });
+  });
+});