rule-matrix

A simple matrix based rules engine that is top down and returns the last match It removes the need for complex if statements and allows business users to define the rules easier using a csv file.

How to use it

MustACHE ability

The engine now has the ability to replace text in the rules with data passed in. Useful to limit the number of situations required to be recorded

var rules = require("rule-matrix")

const rules_ = "operand,equals,result,result,result,result,result,result,result,result,result,result\ntype,string,date,bool,bool,bool,bool,bool,bool,bool,bool,bool\nfield,state,patient.dob,patient.drug_dependent,patient.diagnosed_with_substance_abuse,prescriber.i_am_an_authorised_prescriber,prescription.product_condition_which_does_not_meet_the_general_conditions_for_notification,patient.patient_ever_injected_opioids_or_psychostimulant,patient.patient_currently_using_illicit_substances,patient.ever_treated_for_drug_dependance,patient.evidence_of_intravenous_drug_use,patient.patient_had_a_specialist_assistant\nlabel,State,DOB,Drug Dependent?,Diagnosed with substance abuse?,I am an authorised prescriber,Product condition which does not meet the general conditions for notification,Patient ever injected opioids or psychostimulant,Patient currently using illicit substances,Ever treated for drug dependance,Evidence of intravenous drug use,Patient had a specialist assistant\nvalue,VIC,,required,,,,,,,,\nvalue,NSW,required,required,,,,,,,,\nvalue,QLD,,required,,,,required,required,required,required,\nvalue,SA,required,required,,,,,,,,\nvalue,NT,,,,,,,,,,required\nvalue,WA,required,required,required,required,required,,,,,\nvalue,TAS,,,,,,,,,,"

let obj = {
    state:"VIC"    
}


rules.run(rules_,obj,(results,labels,objects)=>{
    console.log(obj,results,labels,objects)
})
or
let y = await rules.run2(rules_,obj). 

More complex examples to come.

Allowed operands

Operand must be row number 1

Operand	Use	Description
result	Field Manipulation	A data field that is returned
return	Field Manipulation	Same as above
equals or "="	Condition	A matching value
not	Condition	Not equal to
<	Condition	Less than
<=	Condition	Less than or equal to
>	Condition	Greater than
>=	Condition	Greater than or equal to
startsWith	Condition	For strings only.
contains	Condition	For strings only.
endsWith	Condition	For strings only
exists	Condition	Exists

Allowed Types

Type must be row number 2

Type	Description
string
signature	A base64 signature. Treated like a string
double
calc	Uses mathjs. See mathjs for examples. ie:(p-v)/(p+v)
bool
number
date	Uses dayjs. Values can be a Date or NOW for the date now
json	Complex output, Used for result fields only. Syntax to be updated for clarity

The field line

Must be row number 3 The field from the object you are passing in.

label

Must be row number 4 is it exists A label is returned in position 2 of the callback. Useful for dynamic front ends

Value

This is either the value you are comparing against or the value to be returned

Calc is incorporated into a Mustache function

We now have a special field value called calc. When the field type is Number or Double, you can execute a formula using mathjs to return the value. ie: {{#calc}}(p-v){{/calc}}