xpl / stacktracey

stacktracey.js

"use strict";

/*  ------------------------------------------------------------------------ */

const O            = Object,

You seem to be aliasing the built-in name Object as O. This makes your code very difficult to follow, consider using the built-in name directly.

      isBrowser    = (typeof window !== 'undefined') && (window.window === window) && window.navigator,
      lastOf       = x => x[x.length - 1],
      getSource    = require ('get-source'),
      partition    = require ('./impl/partition'),
      asTable      = require ('as-table'),
      nixSlashes   = x => x.replace (/\\/g, '/'),
      pathRoot     = isBrowser ? window.location.href : (nixSlashes (process.cwd ()) + '/')

/*  ------------------------------------------------------------------------ */

class StackTracey extends Array {

    constructor (input, offset) {
        
        const originalInput          = input
            , isParseableSyntaxError = input && (input instanceof SyntaxError && !isBrowser)
        
        super ()

    /*  Fixes for Safari    */

        this.constructor = StackTracey
        this.__proto__   = StackTracey.prototype

    /*  new StackTracey ()            */

        if (!input) {
             input = new Error ()
             offset = (offset === undefined) ? 1 : offset
        }

    /*  new StackTracey (Error)      */

        if (input instanceof Error) {
            input = input[StackTracey.stack] || input.stack || ''
        }

    /*  new StackTracey (string)     */

        if (typeof input === 'string') {
            input = StackTracey.rawParse (input).slice (offset).map (StackTracey.extractEntryMetadata)
        }

    /*  new StackTracey (array)      */

        if (Array.isArray (input)) {

            if (isParseableSyntaxError) {
                
                const rawLines = module.require ('util').inspect (originalInput).split ('\n')
                    , fileLine = rawLines[0].match (/^([^:]+):(.+)/)

                if (fileLine) {
                    input.unshift ({
                        file: nixSlashes (fileLine[1]),
                        line: fileLine[2],
                        column: (rawLines[2] || '').indexOf ('^') + 1,
                        sourceLine: rawLines[1],
                        callee: '(syntax error)',
                        syntaxError: true
                    })
                }
            }

            this.length = input.length
            input.forEach ((x, i) => this[i] = x)
        }
    }

    static extractEntryMetadata (e) {
        
        const fileRelative = StackTracey.relativePath (e.file || '')

        return O.assign (e, {

            calleeShort:  e.calleeShort || lastOf ((e.callee || '').split ('.')),
            fileRelative: fileRelative,
            fileShort:    StackTracey.shortenPath (fileRelative),
            fileName:     lastOf ((e.file || '').split ('/')),
            thirdParty:   StackTracey.isThirdParty (fileRelative) && !e.index
        })
    }

    static shortenPath (relativePath) {
        return relativePath.replace (/^node_modules\//, '')
                           .replace (/^webpack\/bootstrap\//, '')
    }

    static relativePath (fullPath) {
        return fullPath.replace (pathRoot, '')
                       .replace (/^.*\:\/\/?\/?/, '')
    }

    static isThirdParty (relativePath) {
        return (relativePath[0] === '~')                          || // webpack-specific heuristic
               (relativePath[0] === '/')                          || // external source
               (relativePath.indexOf ('node_modules')      === 0) ||
               (relativePath.indexOf ('webpack/bootstrap') === 0)
    }

    static rawParse (str) {

        const lines = (str || '').split ('\n')

        const entries = lines.map (line => { line = line.trim ()

            var callee, fileLineColumn = [], native, planA, planB

The assignment to variable fileLineColumn seems to be never used. Consider removing it.

            if ((planA = line.match (/at (.+) \((.+)\)/)) ||
                (planA = line.match (/(.*)@(.*)/))) {

                callee         =  planA[1]
                native         = (planA[2] === 'native')
                fileLineColumn = (planA[2].match (/(.*):(.+):(.+)/) || []).slice (1) }

            else if ((planB = line.match (/^(at\s+)*(.+):([0-9]+):([0-9]+)/) )) {
                fileLineColumn = (planB).slice (2) }

            else {
                return undefined }

        /*  Detect things like Array.reduce
            TODO: detect more built-in types            */
            
            if (callee && !fileLineColumn[0]) {
                const type = callee.split ('.')[0]
                if (type === 'Array') {
                    native = true
                }
            }

            return {
                beforeParse: line,
                callee:      callee || '',
                index:       isBrowser && (fileLineColumn[0] === window.location.href),
                native:      native || false,
                file:        nixSlashes (fileLineColumn[0] || ''),
                line:        parseInt (fileLineColumn[1] || '', 10) || undefined,
                column:      parseInt (fileLineColumn[2] || '', 10) || undefined } })

        return entries.filter (x => (x !== undefined))
    }

    withSource (i) {
        return this[i] && StackTracey.withSource (this[i])
    }

    static withSource (loc) {

        if (loc.sourceFile || (loc.file && loc.file.indexOf ('<') >= 0)) { // skip things like <anonymous> and stuff that was already fetched
            return loc
            
        } else {
            let resolved = getSource (loc.file || '').resolve (loc)

            if (resolved.sourceFile) {
                resolved.file = resolved.sourceFile.path
                resolved = StackTracey.extractEntryMetadata (resolved)
            }

            if (resolved.sourceLine && resolved.sourceLine.includes ('// @hide')) {
                resolved.sourceLine  = resolved.sourceLine.replace  ('// @hide', '')
                resolved.hide = true
            }

            return O.assign ({ sourceLine: '' }, loc, resolved)
        }
    }

    get withSources () {
        return new StackTracey (this.map (StackTracey.withSource))
    }

    get mergeRepeatedLines () {
        return new StackTracey (
            partition (this, e => e.file + e.line).map (
                group => {
                    return group.items.slice (1).reduce ((memo, entry) => {
                        memo.callee      = (memo.callee      || '<anonymous>') + ' → ' + (entry.callee      || '<anonymous>')
                        memo.calleeShort = (memo.calleeShort || '<anonymous>') + ' → ' + (entry.calleeShort || '<anonymous>')
                        return memo }, O.assign ({}, group.items[0])) }))
    }

    get clean () {
        return this.withSources.mergeRepeatedLines.filter ((e, i) => (i === 0) || !(e.thirdParty || e.hide || e.native))
    }

    at (i) {
        return O.assign ({

            beforeParse: '',
            callee:      '<???>',
            index:       false,
            native:      false,
            file:        '<???>',
            line:        0,
            column:      0

        }, this[i])
    }

    static locationsEqual (a, b) {
        return (a.file   === b.file) &&
               (a.line   === b.line) &&
               (a.column === b.column)
    }

    get pretty () {

        const trimEnd   = (s, n) => (s.length > n) ? (s.slice (0, n-1) + '…') : s        
        const trimStart = (s, n) => (s.length > n) ? ('…' + s.slice (-(n-1))) : s

        return asTable (this.withSources.map (
                            e => [
                                ('at ' + trimEnd (e.calleeShort, 30)),
                                trimStart ((e.fileShort && (e.fileShort + ':' + e.line)) || '', 40),
                                trimEnd (((e.sourceLine || '').trim () || ''), 80)
                            ]))
    }

    static resetCache () {

        getSource.resetCache ()
    }
}

/*  Chaining helper for .isThirdParty
    ------------------------------------------------------------------------ */

(() => {

    const methods = {

        include (pred) {

            const f = StackTracey.isThirdParty
            O.assign (StackTracey.isThirdParty = (path => f (path) ||  pred (path)), methods)
        },

        except (pred) {

            const f = StackTracey.isThirdParty
            O.assign (StackTracey.isThirdParty = (path => f (path) && !pred (path)), methods)
        },
    }

    O.assign (StackTracey.isThirdParty, methods)

}) ()

/*  Array methods
    ------------------------------------------------------------------------ */

;['map', 'filter', 'slice', 'concat', 'reverse'].forEach (name => {

    StackTracey.prototype[name] = function (/*...args */) { // no support for ...args in Node v4 :(
        
        const arr = Array.from (this)
        return new StackTracey (arr[name].apply (arr, arguments))
    }
})

/*  A private field that an Error instance can expose
    ------------------------------------------------------------------------ */

StackTracey.stack = /* istanbul ignore next */ (typeof Symbol !== 'undefined') ? Symbol.for ('StackTracey') : '__StackTracey'

The variable Symbol seems to be never declared. If this is a global, consider adding a /** global: Symbol */ comment.

/*  ------------------------------------------------------------------------ */

module.exports = StackTracey

/*  ------------------------------------------------------------------------ */