simple-squiggle

A restricted subset of Squiggle
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custom_type.js (878B)

      1 var typed = require('../typed-function');
      2 
      3 // create a prototype
      4 function Person(params) {
      5   this.name = params.name;
      6   this.age = params.age;
      7 }
      8 
      9 // register a test for this new type
     10 typed.addType({
     11   name: 'Person',
     12   test: function (x) {
     13     return x instanceof Person;
     14   }
     15 });
     16 
     17 // create a typed function
     18 var stringify = typed({
     19   'Person': function (person) {
     20     return JSON.stringify(person);
     21   }
     22 });
     23 
     24 // use the function
     25 var person = new Person({name: 'John', age: 28});
     26 
     27 console.log(stringify(person));
     28 // outputs: '{"name":"John","age":28}'
     29 
     30 // calling the function with a non-supported type signature will throw an error
     31 try {
     32   stringify('ooops');
     33 }
     34 catch (err) {
     35   console.log('Wrong input will throw an error:');
     36   console.log('  ' + err.toString());
     37   // outputs: TypeError: Unexpected type of argument (expected: Person,
     38   //          actual: string, index: 0)
     39 }