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node_modules/vega-lite/bin/vl2vg

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+#!/usr/bin/env node
+// Compile a Vega-Lite spec to Vega
+
+//@ts-check
+'use strict';
+
+const helpText = `Compile a Vega-Lite spec to Vega.
+
+Usage: vl2vg [vega_lite_json_file] [output_vega_json_file] [-p]
+  If no arguments are provided, reads from stdin.
+  If output_vega_json_file is not provided, writes to stdout.
+  Passing -p formats the generated Vega spec.`;
+
+// import required libraries
+const {createReadStream, createWriteStream} = require('fs');
+const vegaLite = require('../build/vega-lite');
+const compactStringify = require('json-stringify-pretty-compact');
+
+// arguments
+const args = require('yargs')
+  .usage(helpText)
+  .demand(0);
+
+args
+  .boolean('p')
+  .alias('p', 'pretty')
+  .describe('p', 'Output human readable/pretty spec.');
+
+const argv = args.help().version().argv;
+
+/**
+ * Read a file.
+ *
+ * @param file {string} File path
+ */
+function read(file) {
+  return new Promise((resolve, reject) => {
+    const input = file ? createReadStream(file) : process.stdin;
+    let text = '';
+
+    input.setEncoding('utf8');
+    input.on('error', err => reject(err));
+    input.on('data', chunk => (text += chunk));
+    input.on('end', () => resolve(text));
+  });
+}
+
+// load spec, compile vg spec
+read(argv._[0]).then(text => compile(JSON.parse(text)));
+
+/**
+ * Compile the Vega-Lite spec to Vega.
+ *
+ * @param vlSpec {import("../src").TopLevelSpec} The Vega-Lite spec.
+ */
+function compile(vlSpec) {
+  // @ts-ignore
+  const vgSpec = vegaLite.compile(vlSpec).spec;
+
+  const file = argv._[1] || null;
+  const out = file ? createWriteStream(file) : process.stdout;
+  if (argv.p) {
+    out.write(compactStringify(vgSpec) + '\n');
+  } else {
+    out.write(JSON.stringify(vgSpec) + '\n');
+  }
+}