PDFJS Wrapper to handle DD Form 2875.

script.js

/*
    Usage:

    const file = document.getElementById('a_file').files[0];
    const fh = new FileHandler(file);
    console.log(fh.fields.name, fh.fields.email);

*/



var FileHandler = (function() {
    var formDefinitions = {
        fm2875_1: {
            name: '2875',
            fieldNames: [
                null, null, null, null, 'date', 'system', 'systemLocation', 'organization', 'officeSymbol', 'phone', 'email', 'jobTitle', //12
                'address', null, null, null, //16
                null, null, null, null, //20
                null, null, null, 'justification', //24
                null, null, null, null, //28
                null, null, null, null, //32
                null, null, 'name', null, //36
                null, null, null, null, //40
                null, null, null, null, //44
                null, null
            ],
            meta: {
                Author: "WHS/ESD/IMD",
                CreationDate: "D:20140122142956-05'00'",
                Creator: "Adobe LiveCycle Designer ES 9.0",
                Title: "DD Form 2875, System Authorization Access Request, August 2009"
            }
        },
        fm2875_2: {
            name: '2875',
            fieldNames: [
                null, null, null, null,
                null, 'date', 'system', 'systemLocation', //8
                'name', 'organization', 'officeSymbol', 'phone', //12
                'email', 'title', 'address', null, //16
                null, null, null, null, //20
                null, null, null, null, //24
                null, 'justification', null, null, //28
                null, null, null, null, //32
                null, null, null, null, //36
                null, null, null, null, //40
                null, null, null, null, //44
                null, null
            ],
            meta: {
                Author: "WHS/ESD/IMD",
                CreationDate: "D:20090817144620-04'00'",
                Creator: "PScript5.dll Version 5.2",
                Title: "DD Form 2875, System Authorization Access Request, August 2009"
            }
        },
        fm1297: {
            name: '1297',
            fields: function(fh) {
                return new Promise(function(resolve, reject) {
                    fh.pages.forEach(function(page, i) {
                        page.getTextContent().then(function(tc) {});
                        if (i >= fh.pdf.numPages) {
                            resolve();
                        }
                    });
                });
            },
            meta: {
                CreationDate: "D:20171011152854-04'00'",
                Creator: "Adobe LiveCycle Designer 11.0"
            }
        }
    };
    var util = {
        convertDataURIToBinary: function convertDataURIToBinary(dataURI) {
            var BASE64_MARKER = ';base64,';
            var base64Index = dataURI.indexOf(BASE64_MARKER) + BASE64_MARKER.length;
            var base64 = dataURI.substring(base64Index);
            var raw = window.atob(base64);
            var rawLength = raw.length;
            var array = new Uint8Array(new ArrayBuffer(rawLength));
            for (var i = 0; i < rawLength; i++) {
                array[i] = raw.charCodeAt(i);
            }
            return array;
        }
    }

    function FileHandler(file) {
        this.fields = [];
        this.fr = new FileReader();
        this.fr.onload = this.onload.bind(this);
        this.fr.readAsDataURL(file);
        this.isInitialized = false;
        this.oninit = function() {};
        this.pages = [];
    }
    FileHandler.prototype.onload = function(e) {
        var c = this;
        var fileAsArray = util.convertDataURIToBinary(e.target.result);
        PDFJS.getDocument(fileAsArray).then(c.processPDF.bind(this)).then(c.getFormDefinition.bind(this)).then(c.setFields.bind(this)).then(function() {
            c.isInitialized = true;
            c.oninit(c);
        });
    }
    FileHandler.prototype.setFields = function(def) {
        var c = this;
        this.name = def.name;
        this.def = def;
        return Promise(function(resolve, reject) {
            if (def.fields) {
                def.fields(c).then(function() {
                    resolve();
                });
            } else {
                for (var i = 0; i < c.fields.length; i++) {
                    if (def.fieldNames[i]) {
                        c.fields[def.fieldNames[i]] = c.fields[i].fieldValue;
                    }
                }
                resolve();
            }
        });
    }
    FileHandler.prototype.formDefinitions = formDefinitions;
    FileHandler.prototype.processPage = function(page) {
        var c = this;
        this.pages.push(page);
        return page.getAnnotations({
            intent: 'display'
        }).then(function(annotations) {
            annotations.filter(function(an) {
                return an.fieldValue && true;
            }).forEach(function(field) {
                c.fields.push(field);
            });
        });
    }
    FileHandler.prototype.processPDF = function(pdf) {
        this.pdf = pdf;
        var c = this;
        return new Promise(function(resolve, reject) {
            for (var i = 1; i <= pdf.numPages; i++) {
                pdf.getPage(i).then(c.processPage.bind(c)).then(function() {
                    if (i >= pdf.numPages) {
                        pdf.getMetadata().then(resolve);
                    }
                });
            }
        });
    }
    FileHandler.prototype.doesMetaMatch = function(defMeta, meta) {
        for (var key in defMeta) {
            if (defMeta[key] !== meta[key]) {
                return false;
            }
        }
        return true;
    }
    FileHandler.prototype.getFormDefinition = function(meta) {
        var info = meta.info;
        for (var key in this.formDefinitions) {
            var def = this.formDefinitions[key];
            var defMeta = this.formDefinitions[key].meta;
            if (this.doesMetaMatch(defMeta, info)) {
                return this.formDefinitions[key];
            }
        }
        console.warn("No matching meta definitions were found.");
    };
    return FileHandler;
})()