fix(core/reports): fix some expression utils functions

projects/core/models/src/utils/expression-utils.md

@@ -0,0 +1,42 @@
+# Xlsreport indicators and functions
+
+This file documents the scripting language that can be used inside xlsreport to define indicators and
+lists all the functions that are available in the language.
+
+`ALL_VALUES_OF(forms, $field)`  
+Returns an array containing all the values that the specified field takes in the forms.
+The values are converted to strings.
+
+`COUNT_FORMS(forms, $expression?)`  
+Returns the number of forms for which expression evaluates to true,
+for the form itself or for any of its repetitions.
+
+`COUNT_REPS(forms, $expression?)`  
+Counts the forms and all of their repetitions for which the expression evaluates to true.
+
+`COUNT_FORMS_UNIQUE(forms, $field, $expression?)`  
+TODO: rename to COUNT_UNIQUE_VALUES
+Counts the different values that the specified field takes in the forms (and their repetitions).
+
+`LAST(forms, $expression, dateField = "created_at")`  
+Evaluates the expression in the last form by date.
+
+`SUM(forms, $field, $expression?)`  
+Aggregates and sums the values of the specified field.
+An optional expression can be added to filter which forms to take for the sum.
+
+`MEAN(forms, $field, $expression?)`  
+Computes the mean of the values of the specified field.
+An optional expression can be added to filter which forms to take for the sum.
+
+`MAX(forms, $field, $expression?)`  
+Computes the max value of the field.
+An optional expression can be added to filter which forms to take for the sum.
+
+`MEDIAN(forms, $field, $expression?)`  
+Computes the median value of the field.
+An optional expression can be added to filter which forms to take for the sum.
+
+`MODE(forms, $field, $expression?)`  
+Computes the mode value of the field.
+An optional expression can be added to filter which forms to take for the sum.

projects/core/models/src/utils/expression-utils.spec.ts

@@ -76,7 +76,7 @@ describe('COUNT_FORMS', () => {
 describe('MEAN', () => {
   it('should calculate the mean of a value in dataset', () => {
     const result = MEAN(forms, 'dog_puppies');
-    const dog_puppies_mean = '2';
+    const dog_puppies_mean = 2;
     expect(result).toBe(dog_puppies_mean);
   });
 });