fix: standard functions

src/operators.ts

@@ -119,13 +119,27 @@ export const binaryOperators = {
   '**': (val1, val2): string => `${val1}**${val2}`,
 };
 
-export const standardFunctions = {
-  sum: `function ${VARS_PREFIX}sum(arr) { 
+function getSumFn(prefix: string = ''): string {
+  return `function ${prefix}sum(arr) { 
     if(!Array.isArray(arr)) {
       throw new Error('Expected an array');
     }
     return arr.reduce((a, b) => a + b, 0); 
-  }`,
+  }`;
+}
+
+function getAvgFn(prefix: string = ''): string {
+  return `function ${prefix}avg(arr) { 
+    if(!Array.isArray(arr)) {
+      throw new Error('Expected an array');
+    }
+    ${getSumFn()}
+    return sum(arr) / arr.length; 
+  }`;
+}
+
+export const standardFunctions = {
+  sum: getSumFn(VARS_PREFIX),
   max: `function ${VARS_PREFIX}max(arr) { 
     if(!Array.isArray(arr)) {
       throw new Error('Expected an array');
@@ -138,12 +152,7 @@ export const standardFunctions = {
     }
     return Math.min(...arr); 
   }`,
-  avg: `function ${VARS_PREFIX}avg(arr) { 
-    if(!Array.isArray(arr)) {
-      throw new Error('Expected an array');
-    }
-    return ${VARS_PREFIX}sum(arr) / arr.length; 
-  }`,
+  avg: getAvgFn(VARS_PREFIX),
   length: `function ${VARS_PREFIX}length(arr) {
     if(!Array.isArray(arr) && typeof arr !== 'string') {
       throw new Error('Expected an array or string');
@@ -154,9 +163,10 @@ export const standardFunctions = {
     if(!Array.isArray(arr)) {
       throw new Error('Expected an array');
     }
-    const mu = ${VARS_PREFIX}avg(arr);
+    ${getAvgFn()}
+    const mu = avg(arr);
     const diffSq = arr.map((el) => (el - mu) ** 2);
-    return Math.sqrt(${VARS_PREFIX}avg(diffSq));
+    return Math.sqrt(avg(diffSq));
   }`,
   first: `function ${VARS_PREFIX}first(arr) { 
     if(!Array.isArray(arr)) {

test/scenarios/standard_functions/data.ts

@@ -1,16 +1,68 @@
 import { Scenario } from '../../types';
 
+const input = {
+  arr: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10],
+  obj: {
+    foo: 1,
+    bar: 2,
+    baz: 3,
+    quux: 4,
+  },
+};
+
 export const data: Scenario[] = [
   {
-    input: {
-      arr: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10],
-      obj: {
-        foo: 1,
-        bar: 2,
-        baz: 3,
-        quux: 4,
-      },
-    },
+    template: '.arr.avg()',
+    input,
+    output: 5.5,
+  },
+  {
+    template: '.arr.first()',
+    input,
+    output: 1,
+  },
+  {
+    template: '.arr.index(0)',
+    input,
+    output: 1,
+  },
+  {
+    template: '.arr.index(9)',
+    input,
+    output: 10,
+  },
+  {
+    template: '.arr.last()',
+    input,
+    output: 10,
+  },
+  {
+    template: '.arr.length()',
+    input,
+    output: 10,
+  },
+  {
+    template: '.arr.min()',
+    input,
+    output: 1,
+  },
+  {
+    template: '.arr.max()',
+    input,
+    output: 10,
+  },
+  {
+    template: '.arr.stddev()',
+    input,
+    output: 2.8722813232690143,
+  },
+  {
+    template: '.arr.sum()',
+    input,
+    output: 55,
+  },
+  {
+    input,
     output: {
       sum: 55,
       sum2: 55,

test/types.ts

@@ -14,12 +14,6 @@ export type Scenario = {
 
 export namespace Scenario {
   export function getTemplatePath(scenario: Scenario): string {
-    if (scenario.templatePath) {
-      return scenario.templatePath;
-    }
-    if (scenario.mappingsPath) {
-      return scenario.mappingsPath;
-    }
-    return 'template.jt';
+    return scenario.templatePath || scenario.mappingsPath || scenario.template || 'template.jt';
   }
 }