feat: node only cli (#6881)

fixes #6863

bin/args.js

@@ -0,0 +1,56 @@
+module.exports = function (type) {
+  const helpText = `${type === 'vega' ? 'Compile' : 'Render'} a Vega-Lite specification to ${
+    type === 'vega' ? 'Vega' : type.toUpperCase()
+  }.
+Usage: vl2${type} [vega_json_spec_file] [output_${type}_file]
+  If no arguments are provided, reads from stdin.
+  If output_${type}_file is not provided, writes to stdout.
+  For errors and log messages, writes to stderr.
+To load data, you may need to set a base directory:
+  For web retrieval, use '-b http://host/data/'.
+  For files, use '-b file:///dir/data/' (absolute) or '-b data/' (relative).`;
+
+  const args = require('yargs').usage(helpText).demand(0);
+
+  args
+    .string('b')
+    .alias('b', 'base')
+    .describe('b', 'Base directory for data loading. Defaults to the directory of the input spec.');
+
+  args
+    .string('l')
+    .alias('l', 'loglevel')
+    .describe('l', 'Level of log messages written to stderr. One of "error", "warn" (default), "info", or "debug".');
+
+  args
+    .string('c')
+    .alias('c', 'config')
+    .describe('c', 'Vega config object. Either a JSON file or a .js file that exports the config object.');
+
+  args
+    .string('f')
+    .alias('f', 'format')
+    .describe('f', 'Number format locale descriptor. Either a JSON file or a .js file that exports the locale object.');
+
+  args
+    .string('t')
+    .alias('t', 'timeFormat')
+    .describe(
+      't',
+      'Date/time format locale descriptor. Either a JSON file or a .js file that exports the locale object.'
+    );
+
+  if (type === 'svg') {
+    args.boolean('h').alias('h', 'header').describe('h', 'Include XML header and SVG doctype.');
+  }
+
+  args.number('s').alias('s', 'scale').default('s', 1).describe('s', 'Output resolution scale factor.');
+
+  args.number('seed').describe('seed', 'Seed for random number generation.');
+
+  if (type === 'vega') {
+    args.boolean('p').alias('p', 'pretty').describe('p', 'Output human readable/pretty spec.');
+  }
+
+  return args.help().version().argv;
+};

bin/read.js

@@ -0,0 +1,21 @@
+// from vega-cli
+
+const {createReadStream} = require('fs');
+
+module.exports = 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);
+    });
+  });
+};

bin/render.js

@@ -0,0 +1,65 @@
+// modified from vega-cli
+
+const vega = require('vega');
+const path = require('path');
+const args = require('./args');
+const read = require('./read');
+const vegaLite = require('..');
+
+function load(file) {
+  return require(path.resolve(file));
+}
+
+const Levels = {
+  error: vega.Error,
+  warn: vega.Warn,
+  info: vega.Info,
+  debug: vega.Debug
+};
+
+module.exports = function (type, callback, opt) {
+  // parse command line arguments
+  const arg = args(type);
+
+  // set baseURL, if specified. default to input spec directory
+  const base = arg.base || (arg._[0] ? path.dirname(arg._[0]) : null);
+
+  // set log level, defaults to logging warning messages
+  const loglevel = Levels[String(arg.loglevel).toLowerCase()] || vega.Warn;
+
+  // load config file, if specified
+  const config = arg.config ? load(arg.config) : null;
+
+  // set output image scale factor
+  const scale = arg.scale || undefined;
+
+  // use a seeded random number generator, if specified
+  if (typeof arg.seed !== 'undefined') {
+    if (Number.isNaN(arg.seed)) throw 'Illegal seed value: must be a valid number.';
+    vega.setRandom(vega.randomLCG(arg.seed));
+  }
+
+  // locale options, load custom number/time formats if specified
+  const locale = {
+    number: arg.format ? load(arg.format) : null,
+    time: arg.timeFormat ? load(arg.timeFormat) : null
+  };
+
+  // instantiate view and invoke headless render method
+  function render(vlSpec) {
+    const vgSpec = vegaLite.compile(vlSpec).spec;
+    const view = new vega.View(vega.parse(vgSpec, config), {
+      locale: locale, // set locale options
+      loader: vega.loader({baseURL: base}), // load files from base path
+      logger: vega.logger(loglevel, 'error'), // route all logging to stderr
+      renderer: 'none' // no primary renderer needed
+    }).finalize(); // clear any timers, etc
+
+    return (type === 'svg' ? view.toSVG(scale) : view.toCanvas(scale, opt)).then(_ => callback(_, arg));
+  }
+
+  // read input from file or stdin
+  read(arg._[0] || null)
+    .then(text => render(JSON.parse(text)))
+    .catch(err => console.error(err)); // eslint-disable-line no-console
+};

bin/vl2pdf

@@ -1,9 +1,19 @@
-#!/bin/bash
+#!/usr/bin/env node
 
-# Expects the path to a Vega-Lite specification as the first argument.
-# Passes remaining arguments to vg2pdf using npx.
+// Render a Vega-Lite specification to PDF, using node canvas
+const {createWriteStream} = require('fs');
+const render = require('./render');
 
-DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+render(
+  'pdf',
+  function (canvas, arg) {
+    const file = arg._[1] || null;
+    const out = file ? createWriteStream(file) : process.stdout;
+    const stream = canvas.createPDFStream();
+    stream.on('data', chunk => {
+      out.write(chunk);
+    });
+  },
+  {type: 'pdf', context: {textDrawingMode: 'glyph'}}
+);
 
-# only passes the first argument to vl2vg
-$DIR/vl2vg $1 | npx -p vega vg2pdf '' ${@:2}

bin/vl2png

@@ -1,9 +1,12 @@
-#!/bin/bash
+#!/usr/bin/env node
 
-# Expects the path to a Vega-Lite specification as the first argument.
-# Passes remaining arguments to vg2png using npx.
+// Render a Vega-Lite specification to PNG, using node canvas
+const {createWriteStream} = require('fs');
+const render = require('./render');
 
-DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
-
-# only passes the first argument to vl2vg
-$DIR/vl2vg $1 | npx -p vega vg2png '' ${@:2}
+render('png', function(canvas, arg) {
+  const file = arg._[1] || null;
+  const out = file ? createWriteStream(file) : process.stdout;
+  const stream = canvas.createPNGStream();
+  stream.on('data', chunk => { out.write(chunk); });
+});

bin/vl2svg

@@ -1,9 +1,25 @@
-#!/bin/bash
+#!/usr/bin/env node
 
-# Expects the path to a Vega-Lite specification as the first argument.
-# Passes remaining arguments to vg2svg using npx.
+// Render a Vega-Lite specification to SVG
+const {writeFile} = require('fs');
+const render = require('./render');
 
-DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+const svgHeader =
+  '<?xml version="1.0" encoding="utf-8"?>\n' +
+  '<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" ' +
+  '"http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">\n';
 
-# only passes the first argument to vl2vg
-$DIR/vl2vg $1 | npx -p vega vg2svg '' ${@:2}
+render('svg', function (body, arg) {
+  const svg = (arg.h ? svgHeader : '') + body;
+  const file = arg._[1] || null;
+
+  if (file) {
+    // write to file
+    writeFile(file, svg, err => {
+      if (err) throw err;
+    });
+  } else {
+    // write to stdout
+    process.stdout.write(svg);
+  }
+});

bin/vl2vg

@@ -1,65 +1,25 @@
 #!/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.`;
+// Compile a Vega-Lite spec to Vega
 
-// import required libraries
-const {createReadStream, createWriteStream} = require('fs');
-const vegaLite = require('../build/vega-lite');
+const {createWriteStream} = require('fs');
+const vegaLite = require('..');
 const compactStringify = require('json-stringify-pretty-compact');
+const read = require('./read');
+const args = require('./args');
 
-// 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));
-  });
-}
+const arg = args('vega');
 
 // load spec, compile vg spec
-read(argv._[0]).then(text => compile(JSON.parse(text)));
+read(arg._[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 file = arg._[1] || null;
   const out = file ? createWriteStream(file) : process.stdout;
-  if (argv.p) {
+  if (arg.p) {
     out.write(compactStringify(vgSpec) + '\n');
   } else {
     out.write(JSON.stringify(vgSpec) + '\n');