An open source EAS library created by the community, for the community

Installation

You can install the entire EASjs library by running:

  cd my-project
  npm install @globaleas/easjs

Usage/Examples

To generate an EAS alert using EASjs:

const { generateEASAlert } = require('@globaleas/easjs');

const header = 'ZCZC-CIV-ADR-020173+0100-3441707-ERN/LB-';
generateEASAlert(header)

Without any changes to the configuration, it will output the generated SAME alert in the current working directory as output.wav

To generate an EAS alert with a custom configuration:

const { generateEASAlert, MODES } = require('@globaleas/easjs'); // Import the MODES object for configuration

const header = 'ZCZC-CIV-ADR-020173+0100-3441707-ERN/LB-';
generateEASAlert(header, {
    audioPath: 'alert-audio.mp3',
    outputFile: 'final-alert.wav',
    mode: MODES.DIGITAL
})

The output format is selected by the outputFile extension. Use .wav or .mp3. The format option is deprecated, ignored, and accepted for backwards compatibility.

To decode a SAME header using EASjs:

const { decodeSame } = require('@globaleas/easjs')

const result = decodeSame('ZCZC-WXR-TSW-006081-006013-006001-006087-006085+0100-3401900-WJON/BLU-')
console.log(result)

Output:

{
  organization: 'The National Weather Service has issued ',
  event: 'Tsunami Warning',
  locations: 'San Mateo, CA; Contra Costa, CA; Alameda, CA; Santa Cruz, CA; Santa Clara, CA',
  timing: { start: '7:00 PM on December 6', end: '8:00 PM on December 6' },
  sender: 'WJON/BLU',
  formatted: 'The National Weather Service has issued a Tsunami Warning for San Mateo, CA; Contra Costa, CA; Alameda, CA; Santa Cruz, CA; Santa Clara, CA; beginning at 7:00 PM on December 6 and ending at 8:00 PM on December 6. Message from WJON/BLU'
}

SAME header times are calculated in UTC and displayed in the system timezone by default. referenceDate resolves the header to the nearest year and defaults to the current date. Use year to select an exact year and timeZone to control the displayed timezone:

const result = decodeSame(header, {
    referenceDate: '2026-01-01T00:00:00Z',
    timeZone: 'UTC'
})

const historicalResult = decodeSame(header, {
    year: 2024,
    timeZone: 'UTC'
})

SAME header validation

decodeSame and generateEASAlert validate originator and event codes, one to 31 six-digit location codes, JJJHHMM timestamps, and sender IDs containing one to eight uppercase letters, numbers, or slashes with optional trailing spaces. Validity periods may be 15, 30, or 45 minutes, then half-hour increments through 99 hours and 30 minutes. A missing final dash is added automatically. During generation, shorter sender IDs are padded to eight characters.

generateEASAlert returns a promise and rejects invalid headers, unsupported modes, missing or invalid audio, and output conversion failures:

try {
    await generateEASAlert(header, { mode: MODES.DEFAULT })
} catch (error) {
    console.error(error.message)
}

When migrating to 0.3.0, replace arbitrary generator strings with complete SAME headers and handle rejected promises:

await generateEASAlert('ZCZC-CIV-ADR-020173+0100-3441707-ERN/LB-')

To grab a specific value from the decoded data:

const { decodeSame } = require('@globaleas/easjs')

const result = decodeSame('ZCZC-WXR-TSW-006081-006013-006001-006087-006085+0100-3401900-WJON/BLU-')
console.log(result.organization)

Output:

The National Weather Service has issued

To only translate an event code:

const { eventTranslator } = require('@globaleas/easjs')

const result = eventTranslator('TSW')
console.log(result)

Output:

Tsunami Warning

To translate a FIPS code:

const { translateFips } = require('@globaleas/easjs')

const result = translateFips('006081')
console.log(result)

Output:

{
  subdivision: 'All',
  county: 'San Mateo',
  region: 'CA',
  formatted: 'All San Mateo, CA'
}

To translate an originator:

const { origTranslator } = require('@globaleas/easjs')

const result = origTranslator('PEP')
console.log(result)

Output:

United States Government

Support

For support or queries, open a issue here on GitHub or email developers@globaleas.org