Integer coercion is misleading

[zerkms]

The coerce function for the integers is defined as

export var GraphQLInt = new GraphQLScalarType({
  name: 'Int',
  coerce(value) {
    var num = +value;
    return num === num && num <= MAX_INT && num >= MIN_INT ? num | 0 : null;
  },
  coerceLiteral(ast) {
    if (ast.kind === Kind.INT) {
      var num = parseInt(ast.value, 10);
      if (num <= MAX_INT && num >= MIN_INT) {
        return num;
      }
    }
  }
});

Which means that if a number does not fit the 32 bits, then the significant bits will be truncated.

Which is generally a not expected behaviour, since the coercion must either produce a valid result, or a null.

References:

• https://github.com/graphql/graphql-js/blob/master/src%2Ftype%2Fscalars.js#L20

[leebyron]

Thanks for the report, I'll add tests

[zerkms]

@leebyron sorry for disturbing, but in es6/2015 there is a Math.trunc() that could help eliminate the entire (num < 0 ? Math.ceil : Math.floor) expression

[leebyron]

I'm aware of this, but decided to not require a global object polyfill since GraphQL.js should be included as a side-effect-free library.