codama-idl-codama/packages/nodes/docs

Node (abstract)

The Node type helper represents all available nodes. Note that Node is a type alias and cannot be used directly as a node. Instead you may use any node to satisfy the Node type. You can see all available nodes here.

Functions

Some helper functions are also available to work with nodes.

isNode(node, kind)

Type guard that checks if a node is of a specific kind or part of a list of kinds. If the provided node is null or undefined, the function returns false.

isNode(stringTypeNode('utf8'), 'stringTypeNode'); // true.
isNode(stringTypeNode('utf8'), 'numberTypeNode'); // false.
isNode(stringTypeNode('utf8'), ['stringTypeNode', 'numberTypeNode']); // true.
isNode(null, 'stringTypeNode'); // false.
isNode(undefined, 'stringTypeNode'); // false.

assertIsNode(node, kind)

Type guard that asserts that a node is of a specific kind or part of a list of kinds. If the provided node is null or undefined, the function throws an error.

assertIsNode(stringTypeNode('utf8'), 'stringTypeNode'); // Ok.
assertIsNode(stringTypeNode('utf8'), 'numberTypeNode'); // Throws an error.
assertIsNode(stringTypeNode('utf8'), ['stringTypeNode', 'numberTypeNode']); // Ok.
assertIsNode(null, 'stringTypeNode'); // Throws an error.
assertIsNode(undefined, 'stringTypeNode'); // Throws an error.

isNodeFilter(kind)

This function returns a function that acts as the isNode function but with a predefined kind or list of kinds to check against. This is a useful function to use in combination with array functions like filter.

myNodes.filter(isNodeFilter('stringTypeNode')); // Keep only string type nodes.
myNodes.filter(isNodeFilter(['stringTypeNode', 'numberTypeNode'])); // Keep only string and number type nodes.

assertIsNodeFilter(kind)

This function returns a function that acts as the assertIsNode function but with a predefined kind or list of kinds to check against. This is a useful function to use in combination with array functions like filter.

myNodes.filter(assertIsNodeFilter('stringTypeNode')); // Fail if there are non-string type node.
myNodes.filter(assertIsNodeFilter(['stringTypeNode', 'numberTypeNode'])); // Fail if there are nodes that are not string or number type nodes.

removeNullAndAssertIsNodeFilter(kind)

This function acts like the assertIsNodeFilter function below but removes null and undefined values before asserting the kind or kinds.

const myNodes = [null, stringTypeNode('utf8'), undefined, stringTypeNode('base58')];

myNodes.filter(removeNullAndAssertIsNodeFilter('stringTypeNode')); // Ok and removes null and undefined values.
myNodes.filter(removeNullAndAssertIsNodeFilter('numberTypeNode')); // Throws an error.
myNodes.filter(removeNullAndAssertIsNodeFilter(['stringTypeNode', 'numberTypeNode'])); // Ok and removes null and undefined values.