json-shrinker.js

function jsonShrink(json: any) {
  switch(jsonType(json)) {
    case 'number':
    case 'boolean':
    case 'string':
      // TODO: delegate to jsverify's shrinker
      return [];
    case 'null':
     return [];
    case 'array':
      var res: any[] = []

      // 1. An array can be simplified into one of its elements
      for(var e of json) {
        res.push(e);
      }

      // 2. An array can be simplified by simplifying one of its elements
      for(var i = 0; i < json.length; i++) {
        var e = json[i];
        for(var r of jsonShrink(e)) {
          var a: any[] = [];
          for(var j = 0; j < json.length; j++) {
            if(i === j) {
              a.push(r);
            } else {
              a.push(json[j]);
            }
          }
          res.push(a);
        }
      }
      
      // 2. An array can be simplified by removing one of its elements
      for(var i = 0; i < json.length; i++) {
        var a: any[] = [];
        for(var j = 0; j < json.length; j++) {
          if(j != i) {
            a.push(json[j]);
          }
        }
        res.push(a);
      }
      
      return res;
    case 'object':
      var keys = Object.keys(json);
      var res: any[] = [];

      for(var k of keys) {
        // 1. An object can be simplified into one of it keys
        res.push(k);
        
        // 2. An object can be simplified into one of its values
        res.push(json[k]);
      }

      // 3. An object can be simplified by simplifying one of its keys
      for(var k of keys) {
        for(var r of jsonShrink(k)) {
          if(keys.indexOf(r) !== -1) {
            continue;
          }
          var o: any = {};
          for(var m of keys) {
            if(m === k) {
              o[r] = json[m];
            } else {
              o[m] = json[m];
            }
          }
          res.push(o);
        }
      }

      // 3. An object can be simplified by simplifying one of its values
      for(var k of keys) {
        for(var r of jsonShrink(json[k])) {
          var o: any = {};
          for(var m of keys) {
            if(m === k) {
              o[m] = r;
            } else {
              o[m] = json[m];
            }
          }
          res.push(o);
        }
      }
      
      // 4. An object can be simplified by removing one of its key/value pairs
      for(var k of keys) {
        var o: any = {};
        for(var m of keys) {
          if(k !== m) {
            o[m] = json[m];
          }
        }
        res.push(o);
      }
      
      return res;
  }
}