Build a dynamic string to filter a rest call-CodePudding

I'm trying to build a dynamic string but I'm facing a problem, so I kindly ask help to the community.

A have a string to build a rest call filter, but I'm lost with the and's

This query only works if only one filter condition is provided, but I have to provide as AND

var query;
var queryDefault = "IsLastForLevelAndParticipant eq 1";
this.state.participantFirstName
? query  = "substringof('"    this.state.participantFirstName   "',Participant/FirstName)" 
: queryDefault
this.state.participantLastName
? query  = "substringof('"    this.state.participantLastName   "',Participant/LastName)" 
: queryDefault

So let´s see.

If I start building this and only one filter is provided I'll have a plus and

var query;
var queryDefault = "IsLastForLevelAndParticipant eq 1";
this.state.participantFirstName
? query  = "substringof('"    this.state.participantFirstName   "',Participant/FirstName) and " 
: queryDefault
this.state.participantLastName
? query  = "substringof('"    this.state.participantLastName   "',Participant/LastName)" 
: queryDefault

query  = " and "   queryDefault

I have 12 filters and I must know how many have values in order to provide the and clause

This is my state

//Filters Certificates
startEmission: string;
endEmission: string;
startValidity: string;
endValidity: string;
participantFirstName: string;
participantLastName: string;
paticipantCertNumber: string;
selectYesNo: string;
selectLevel: string;

Any help is a bonus.

CodePudding user response：

Add all possible filters to an array, filter the falsy values and finally join all items with " and ".

var query = [
  queryDefault,
  this.state.participantFirstName && "substringof('"   this.state.participantFirstName   "',Participant/FirstName)"
  this.state.participantLastName && "substringof('"   this.state.participantLastName   "',Participant/LastName)"
]
.filter(item => !!item)
.join(" and ");

BTW. are you using OData? the structure of the filter looks familiar. If you do, I would recommend you to use this library: https://github.com/techniq/odata-query#readme

CodePudding user response：

Since I'm using datetime also, here it is the final solution

var queryDefault = "IsLastForLevelAndParticipant eq 1";
var query = [
  queryDefault,
  this.state.startEmission && "(Date1 ge datetime'"   moment.utc(this.state.startEmission).toISOString()   "') and (Date1 le datetime'" 
      moment.utc(this.state.endEmission).toISOString()   "')",
  this.state.startValidity && "(Validto ge datetime'"   moment.utc(this.state.startValidity).toISOString()   "') and (Validto le datetime'" 
      moment.utc(this.state.endValidity).toISOString()   "')",
  this.state.participantFirstName && "(substringof('"   this.state.participantFirstName   "',Participant/FirstName))",
  this.state.participantLastName && "(substringof('"   this.state.participantLastName   "',Participant/LastName))",
  this.state.selectYesNo && "IsPrinted eq "   this.state.selectYesNo,
  this.state.selectLevel && "Level/Title eq '"   this.state.selectLevel   "'"
]

.filter(filter => !! filter)
.join(" and ");

var q = JSON.stringify(query).substring(1).slice(0, -1);
console.log(JSON.stringify(query));