UNPKG

aws-ddk-core

Version:

The AWS DataOps Development Kit is an open source development framework for customers that build data workflows and modern data architecture on AWS.

78 lines (74 loc) 2.4 kB
'use strict'; var identity = require('../nodes/identity.js'); var visit = require('../visit.js'); /** * Verify that the input string is a valid anchor. * * Will throw on errors. */ function anchorIsValid(anchor) { if (/[\x00-\x19\s,[\]{}]/.test(anchor)) { const sa = JSON.stringify(anchor); const msg = `Anchor must not contain whitespace or control characters: ${sa}`; throw new Error(msg); } return true; } function anchorNames(root) { const anchors = new Set(); visit.visit(root, { Value(_key, node) { if (node.anchor) anchors.add(node.anchor); } }); return anchors; } /** Find a new anchor name with the given `prefix` and a one-indexed suffix. */ function findNewAnchor(prefix, exclude) { for (let i = 1; true; ++i) { const name = `${prefix}${i}`; if (!exclude.has(name)) return name; } } function createNodeAnchors(doc, prefix) { const aliasObjects = []; const sourceObjects = new Map(); let prevAnchors = null; return { onAnchor: (source) => { aliasObjects.push(source); if (!prevAnchors) prevAnchors = anchorNames(doc); const anchor = findNewAnchor(prefix, prevAnchors); prevAnchors.add(anchor); return anchor; }, /** * With circular references, the source node is only resolved after all * of its child nodes are. This is why anchors are set only after all of * the nodes have been created. */ setAnchors: () => { for (const source of aliasObjects) { const ref = sourceObjects.get(source); if (typeof ref === 'object' && ref.anchor && (identity.isScalar(ref.node) || identity.isCollection(ref.node))) { ref.node.anchor = ref.anchor; } else { const error = new Error('Failed to resolve repeated object (this should not happen)'); error.source = source; throw error; } } }, sourceObjects }; } exports.anchorIsValid = anchorIsValid; exports.anchorNames = anchorNames; exports.createNodeAnchors = createNodeAnchors; exports.findNewAnchor = findNewAnchor;