Pretty print GraphQL API Schema Introspection Results

pretty_print_introspection.js

function resolveType(type){
  var stack = []

  var current = type;
  while(current != null) {
    stack.push({kind:current.kind, name:current.name})
    current = current.ofType;
  }

  var output = "";
  if(stack.length == 0){
  return null;
  }

  while(stack.length > 0) {
    var token = stack.pop()
    if(token.kind == "NON_NULL") {
      output = "!"+output;
    }
    else if(token.kind == "LIST") {
      output = "["+output+"]";
    }
    else {
      output = token.name;
    }
  }

  return output;
}

function dumpFields(objectType, objectName, inputFields){
  if(!inputFields){ inputFields = [] }
  return objectType + " " + objectName + "\n  "+ inputFields.map(x => {
  var type = resolveType(x.type);

  var methodSuffix = "";
  if(x.args && x.args.length > 0) {
    methodSuffix = "("+x.args.map(arg => {

      var defaultValue = "";
      if(arg.defaultValue) {
        defaultValue = "="+arg.defaultValue;
      }

      return arg.name+":"+resolveType(arg.type)+defaultValue;


  }).join(", ")+")";
}

return {name:x.name+methodSuffix, type:type}}).sort((a,b) => a.name.localeCompare(b.name)).map(x => x.type+" "+x.name).join("\n  ")
}

function prettyPrintSchema(schema) {

  var target = schema;

  var types = target.data.__schema.types.sort((a,b) => a.name.localeCompare(b.name)).map((type) => {

  var kind = null;
  if(type.kind) {
    kind = type.kind[0]+type.kind.slice(1).toLocaleLowerCase();
  }

  if(type.kind === "ENUM") {
    return dumpFields(kind, type.name, type.enumValues)
  }

  if(type.kind === "INPUT_OBJECT") {
    return dumpFields(kind, type.name, type.inputFields)
  }

  if(type.kind === "INTERFACE") {
    var implementedBy = type.possibleTypes.map(type => type.name).join(", ");
    var suffix = "none?"
    if(implementedBy.length > 0) {
      suffix = implementedBy;
    }
    return dumpFields(kind, type.name+" implemented by "+suffix, type.fields)
  }


  return dumpFields(kind, type.name, type.fields)
  }).join("\n\n")

  var directives = target.data.__schema.directives.map((directive) => {
    return dumpFields("Directive ("+directive.locations.join(", ")+")", directive.name, directive.args)
  }).join("\n\n")
  return directives+"\n\n"+types;
}

copy( prettyPrintSchema(fetchedSchema));