Can be safely closed. This is not a valid question anymore.
You should be using JSON.parse() to parse JSON, since body and Message are JSON strings.
const records = [{
messageId: '1',
body: '{"Message" : "{\\"detail\\": {\\"documentType\\": \\"pm1"\\", \\"documentDate\\": \\"2018-08-27 04:00:00\\"}}"}',
},
{
messageId: '2',
body: '{"Message" : "{\\"detail\\": {\\"documentType\\": \\"pm3\\", \\"documentDate\\": \\"2018-08-27 04:00:00\\"}}"}',
},
{
messageId: '3',
body: '{"Message" : "{\\"detail\\": {\\"documentType\\": \\"pm8\\", \\"documentDate\\": \\"2018-08-27 04:00:00\\"}}"}',
},
];
let output = [];
let message = [];
output = records.filter((resource) => {
console.log('resource:', resource);
const body = resource.body ? JSON.parse(resource.body) : {};
message = body.message ? JSON.parse(body.Message) : {};
console.log('message:', message);
const documentType = message?.detail?.documentType?.toLowerCase() || '';
console.log('decoumentType:', documentType);
const acceptedDocTypes = ['pm1', 'pm2', 'pm3', 'pm4', 'pm5'];
return acceptedDocTypes.includes(documentType);
});If your backslashes are consistent, you can try removing them using a regex:
const records = [
{
messageId: '2',
body: '{"Message" : "{\\"detail\\": {\\"documentType\\": \\"pm3\\", \\"documentDate\\": \\"2018-08-27 04:00:00\\"}}"}',
},
{
messageId: '3',
body: '{"Message" : "{\\"detail\\": {\\"documentType\\": \\"pm8\\", \\"documentDate\\": \\"2018-08-27 04:00:00\\"}}"}',
},
]
records.forEach(record => record.body = record.body.replace(/(\\+")/gmi, '"'))
records.forEach(record => record.body = record.body.replace(/\s*"\s*\{/gmi, '{').replace(/\s*\}\s*"/gmi, '}'))
records.forEach(record => record.body = JSON.parse(record.body))
console.log(records)In this way, you first clean the input, then you can apply JSON.parse. This doesn't work with your first example since there's an extra unescaped quote, but I suppose it was a typo in your writing.