bson-transpilers

BSON-Transpilers

Transpilers for building BSON documents in any language. Current support provided for shell and javascript as inputs. java, c# and python as outputs.

Usage

const transpiler = require('bson-transpilers');

const input = 'javascript';
const output = 'java';

const string =`
{ item: "book", qty: Int32(10), tags: ["red", "blank"], dim_cm: [14, Int32("81")] }`;

try {
  const compiledString = transpiler[input][output].compile(string);
  console.log(compiledCode);
  // new Document("item", "book").append("qty", 10)
  // .append("tags", Arrays.asList("red", "blank"))
  // .append("dim_cm", Arrays.asList(14L, 81")))
} catch (error) {
  console.error(error);
}

API

compiledString = transpiler[inputLang][outputLang].compile(codeString)

Output a compiled string given input and output languages.

• inputLang: Input language of the code string. shell and javascript are currently supported.
• outputLang: The language you would like the output to be. java, python, shell, javascript, and csharp are currently supported.
• codeString: The code string you would like to be compiled to your selected output language.

importsString = transpiler[inputLang][outputLang].getImports()

Output a string containing the set of import statements for the generated code to compile. These are all the packages that the compiled code could use so that the transpiler output will be runnable.

catch (error)

Any transpiler errors that occur will be thrown. To catch them, wrap the transpiler in a try/catch block.

• error.message: Message bson-transpilers will send back letting you know the transpiler error.
• error.stack: The usual error stacktrace.
• error.code: Error code that bson-transpilers adds to the error object to help you distinguish error types.
• error.line: If it is a syntax error, will have the line.
• error.column: If it is a syntax error, will have the column.
• error.symbol: If it is a syntax error, will have the symbol associated with the error.

Errors

There are a few different error classes thrown by bson-transpilers, each with their own error code:

BsonTranspilersArgumentError

code: E_BSONTRANSPILERS_ARGUMENT

This will occur when you're using a method with a wrong number of arguments, or the arguments are of the wrong type. For example, ObjectId().equals() requires one argument and it will throw if anything other than one argument is provided:

// ✘: this will throw a BsonTranspilersArgumentError.
ObjectId().equals(ObjectId(), ObjectId());

// ✔: this won't throw
ObjectId().equals(ObjectId());

// ✘: this will throw a BsonTranspilersArgumentError.
ObjectId({});

// ✔: this won't throw
ObjectId();

BsonTranspilersAttributeError

code: E_BSONTRANSPILERS_ATTRIBUTE

Will be thrown if an invalid method or property is used on a BSON object. For example, since new DBRef() doesn't have a method .foo(), transpiler will throw:

// ✘: method foo doesn't exist, so this will throw a BsonTranspilersAttributeError .
new DBRef('newCollection', new ObjectId()).foo()

// ✔: this won't throw, since .toString() method exists
new DBRef('newCollection', new ObjectId()).toString(10)

BsonTranspilersSyntaxError

code: E_BSONTRANSPILERS_SYNTAX

This will throw if you have a syntax error. For example missing a colon in Object assignment, or forgetting a comma in array definition:

// ✘: this is not a proper object definition; will throw E_SYNTAX_GENERIC
{ key 'beep' }

// ✘: this is not a proper array definition, will throw E_SYNTAX_GENERIC
[ 'beep'; 'boop' 'beepBoop' ]

// ✔: neither of these will throw 
{ key: 'beep' }
[ 'beep', 'boop', 'beepBoop' ]

BsonTranspilersTypeError

code: E_BSONTRANSPILERS_TYPE

This error will occur if a symbol is treated as the wrong type. For example, if a non-function is called:

// ✘: MAX_VALUE is a constant, not a function
Long.MAX_VALUE()

// ✔: MAX_VALUE without a call will not throw
Long.MAX_VALUE

BsonTranspilersUnimplementedError

code: E_BSONTRANSPILERS_UNIMPLEMENTED

If there is a feature in the input code that is not currently supported by the transpiler.

BsonTranspilersRuntimeError

code: E_BSONTRANSPILERS_RUNTIME

A generic runtime error will be thrown for all errors that are not covered by the above list of errors. These are usually constructor requirements, for example when using a RegExp() an unsupported flag is given:

// ✘: these are not proper 'RegExp()' flags, a BsonTranspilersRuntimeError will be thrown.
new RegExp('ab+c', 'beep')

// ✔: 'im' are proper 'RegExp()' flags
new RegExp('ab+c', 'im')

BsonTranspilersInternalError

code: E_BSONTRANSPILERS_INTERNAL

In the case where something has gone wrong within compilation, and an error has occured. If you see this error, please create an issue on Github!

Install

npm install -S bson-transpilers

Contributing

Head over to the readme on contributing to find out more information on project structure and setting up your environment.

Authors

• aherlihy - Anna Herlihy [e-mail]
• alenakhineika - Alena Khineika [e-mail]
• lrlna - Irina Shestak [e-mail]

License

Apache-2.0