ensemble_ts_interpreter 1.0.0

ensemble_ts_interpreter: ^1.0.0 copied to clipboard

This is a javascript ES5 parser and interpreter written entirely in dart.

What it is #

• Primary use case is to let users type in simple js that you want to execute inline. This should be not used as a general replacement for dart in flutter
• Runs in the same process as your Dart/Flutter code so no need to use the browser's javascript engine. As a result, this is fast.
• Unlike react native, doesn't require any bridge or have memory issues
• Supports most common use cases right now such as functions, lists, all primitive types (string, number, arrays, dates) etc.
• Highly extensible. The context object could be json or any dart object enhanced with the Invokable mixin (see below)

How to use #

• in your pubspec.yaml, add the following line under dependencies -

  ensemble_ts_interpreter:
    git:
      url: https://github.com/EnsembleUI/ensemble_ts_interpreter.git
      ref: master

• run flutter pub upgrade
• Simply call the JSInterpreter with the code you want to evaluate while passing it the context.

JSInterpreter.fromCode(code, context).evaluate();

context is the key object here. You can pass json as context (see examples below) or pass an instance of Invokable which could be any Dart object.

Examples #

All the examples are in the unit test suite - new_interpreter_tests

Listing some here.

Filter a list

    Map<String, dynamic> context = {
      'items': ['one', 'two', 'three'],
      'nested': [
        {'id': 1, 'label': 'eggs', 'type': ''},
        {'id': 2, 'label': 'strawberry', 'type': 'fruit'},
        {'id': 3, 'label': 'nut'}
      ]
    };

    String code = """
      var flatList = items.filter(function(e) {
        return e != 'two';
      });
      
      var nestedList = nested.filter(function(e) {
        return e['type'] == 'fruit'
      });
    """;
    
    JSInterpreter.fromCode(code, context).evaluate();

Different String functions

    Map<String, dynamic> context = initContext();

    String code = """
        var arr = ['a','b','c','d'];
        var b = arr.at(1);
        var arr2 = arr.concat(['e','f']);
        var f = arr2.find(function (element)  { 
              var rtn = ( element == 'f' )? true : false;
              return rtn;
         });
         var includes = arr2.includes('e');
         var str = arr.join();
         var str2 = arr.join('-');
         var str3 = arr.join('');
         var last = arr2.pop(); 
         var nums = [1,2,3,4,5];
         var sum = nums.reduce(function (value, element) {
            return value + element;
            });
         var reversed = arr.reverse();
        """;

    JSInterpreter.fromCode(code, context).evaluate();

Function Declaration and then calling the functions

  test('functiondeclarationtext', () async {
    String codeToEvaluate = """
      var i = 0;
      var users = [{'name':'Khurram'},{'name':'Mahmood'}];
      updateSalary(users,noArgFunction());
      return manyParms(users[0],noArgFunction()[0],'Hello','How','are','you','today,');
      function noArgFunction() {
        var salaries = [10000,200000];
        salaries[1] = 900000;
        return salaries;
      }
      function updateSalary(users,salaries) {
        users.map(function(user) {
          user['salary'] = salaries[i];
          user['age'] = age;
          i++;
        });
      }
      function manyParms(user,salary,a,b,c,d,e) {
        return a+' '+b+' '+c+' '+d+' '+e+' '+user.name+'. You made \$'+salary;
      }
        
      """;
    Map<String, dynamic> context = initContext();
    dynamic rtnValue = JSInterpreter.fromCode(codeToEvaluate,context).evaluate();
    expect(context['users'][0]['name'],'Khurram');
    expect(context['users'][0]['salary'],10000);
    expect(context['users'][1]['salary'],900000);
    expect(context['users'][1]['age'],3);
    expect(rtnValue,'Hello How are you today, Khurram. You made \$10000');
  });