modern-netcdf/bin/dump.js

Modern NetCDF file reader and utilities

#!/usr/bin/env node

const fs = require('fs');
const path = require('path');
const { NetCDFReader } = require('..');

function formatValue(value) {
  if (Array.isArray(value)) {
    // Handle large arrays by limiting output
    if (value.length > 100) {
      return `[${value.length} values]`;
    }
    return value.join(', ');
  }
  if (typeof value === 'string' && value.length > 1000) {
    return `[string length ${value.length}]`;
  }
  return value;
}

function formatAttributes(attrs) {
  return attrs.map(attr => `                ${attr.name} = ${formatValue(attr.value)} ;`).join('\n');
}

async function dump(filePath) {
  const buf = fs.readFileSync(filePath);
  const reader = await NetCDFReader.open(buf);
  const fileName = path.basename(filePath, '.nc');
  
  console.log(`netcdf ${fileName} {`);
  console.log('dimensions:');
  for (const dim of reader.dimensions) {
    console.log(`        ${dim.name} = ${dim.size} ;`);
  }
  
  console.log('variables:');
  for (const [name, variable] of Object.entries(reader.variables)) {
    const dimNames = (variable.dimensions || []).map((d) => d.name);
    console.log(`        ${variable.type} ${name}${dimNames.length ? `(${dimNames.join(', ')})` : ''} ;`);
    if (variable.attributes.length) {
      console.log(formatAttributes(variable.attributes));
    }
  }
  
  console.log('\n// global attributes:');
  console.log(formatAttributes(reader.globalAttributes));
  
  console.log('\ndata:');
  for (const [name, variable] of Object.entries(reader.variables)) {
    const data = await variable.read();
    console.log(`\n ${name} =`);
    console.log(`  ${formatValue(data)} ;`);
  }
  
  console.log('}');
  reader.close();
}

if (require.main === module) {
  const filePath = process.argv[2];
  if (!filePath) {
    console.error('Usage: node dump.js <path-to-netcdf-file>');
    process.exit(1);
  }
  dump(filePath).catch(err => {
    console.error(err);
    process.exit(1);
  });
}