Current File : //lib/node_modules/ncm-ng/lib/json.js
'use strict'
// General JSON parser that logs errors and returns undefined on failure.
exports.parse = parse
exports.parseAsync = parseAsync
exports.lineify = lineify
const pDefer = require('p-defer')
const nsUtil = require('../util')
const logger = nsUtil.logger.getLogger(__filename)
function parse (content) {
if (content == null) return null
if (typeof content !== 'string') {
const err = new Error('parse() called with non-string parameter')
logger.error(err)
return undefined
}
try {
return JSON.parse(content)
} catch (err) {
const slice = content.slice(0, 30)
logger.error(`parse() called with non-JSON content: "${slice}...": ${err}`)
return undefined
}
}
// This function just breaks up JSON parse to keep it in it's own
// event loop. For processing that includes parsing a large JSON
// wad, this may help keeping the el from blocking.
async function parseAsync (content) {
const deferred = pDefer()
let result
setImmediate(doParse)
return deferred.promise
// do the parse only in a tick
function doParse () {
result = parse(content)
setImmediate(sendResponse)
}
function sendResponse () {
deferred.resolve(result)
}
}
// convert a "small" JSON object to a nice line representation
function lineify (object, isSubObject) {
const result = []
if (typeof object === 'string') return JSON.stringify(object)
if (typeof object === 'number') return `${object}`
if (typeof object === 'boolean') return `${object}`
if (object === undefined) return 'undefined'
if (object == null) return 'null'
if (isSubObject) result.push('{')
for (let key of Object.keys(object)) {
result.push(`${key}:`)
result.push(lineify(object[key], true))
}
if (isSubObject) result.push('}')
return result.join(' ')
}
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