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The previous version is here. This version takes suggestions from that review into account:

The previous version is here. This version takes suggestions from that review into account:

(function(global){
 
 // Find start and end positions of each loop.
 function findLoops(code) {
 var start;
 var startpoints = {};
 var endpoints = {};
 var stack = [];
 
 for (var i = 0; i < code.length; i++) {
 if (code[i] == '[') {
 stack.push(i);
 } else if (code[i] == ']') {
 start = stack.pop();
 startpoints[i] = start;
 endpoints[start] = i;
 }
 }
 
 return { start: startpoints, end: endpoints };
 }
 
 // Run the brainfuck interpreter.
 function run(source) {
 var brainfuck = this;
 var code = source.replace(/[^-+<>.,[\]]/g, '').split(''); // program code
 var loop = findLoops(code); // loop start and end positions
 var data = []; // array of data cells stored by the program code
 var cell = 0; // index in the data array representing one "cell" of data
 var next = 0; // index in the code array of the next instruction to run 
 var operation = {
 '>': function () { ++cell; },
 '<': function () { --cell; },
 '+': function () { data[cell] = (data[cell] || 0) + 1; },
 '-': function () { data[cell] = (data[cell] || 0) - 1; },
 '.': function () { brainfuck.write(data[cell]); },
 ',': function () { data[cell] = brainfuck.read(); },
 '[': function () { if (!data[cell]) { next = loop.end[next]; } },
 ']': function () { if (data[cell]) { next = loop.start[next]; } }
 };
 
 while (next < code.length) {
 operation[code[next]]();
 next++;
 }
 
 if (brainfuck.end) {
 brainfuck.end();
 }
 }
 
 // Export a module for AMD loaders, CJS environments, or as a global.
 function exportModule(name, module) {
 if (global['define'] && global['define']['amd']) {
 global['define'](module);
 } else if (global['exports']) {
 for (var key in value) if (value.hasOwnProperty(key)) {
 global['exports'][key] = module[key];
 }
 } else {
 global[name] = module;
 }
 }
 
 // Export brainfuck module. 
 exportModule('brainfuck', { 
 'run': run,
 'read': function() { throw new Error('"read" function not provided'); },
 'write': function() { throw new Error('"write" function not provided'); }
 });
 
}(this));

Test it out here. I have no specific concerns at this point, I'm just looking for a general review.

(function(global){
 
 // Find start and end positions of each loop.
 function findLoops(code) {
 var start;
 var startpoints = {};
 var endpoints = {};
 var stack = [];
 
 for (var i = 0; i < code.length; i++) {
 if (code[i] == '[') {
 stack.push(i);
 } else if (code[i] == ']') {
 start = stack.pop();
 startpoints[i] = start;
 endpoints[start] = i;
 }
 }
 
 return { start: startpoints, end: endpoints };
 }
 
 // Run the brainfuck interpreter.
 function run(source) {
 var brainfuck = this;
 var code = source.replace(/[^-+<>.,[\]]/g, '').split(''); // program code
 var loop = findLoops(code); // loop start and end positions
 var data = []; // array of data cells stored by the program code
 var cell = 0; // index in the data array representing one "cell" of data
 var next = 0; // index in the code array of the next instruction to run 
 var operation = {
 '>': function () { ++cell; },
 '<': function () { --cell; },
 '+': function () { data[cell] = (data[cell] || 0) + 1; },
 '-': function () { data[cell] = (data[cell] || 0) - 1; },
 '.': function () { brainfuck.write(data[cell]); },
 ',': function () { data[cell] = brainfuck.read(); },
 '[': function () { if (!data[cell]) { next = loop.end[next]; } },
 ']': function () { if (data[cell]) { next = loop.start[next]; } }
 };
 
 while (next < code.length) {
 operation[code[next]]();
 next++;
 }
 
 if (brainfuck.end) {
 brainfuck.end();
 }
 }
 
 // Export a module for AMD loaders, CJS environments, or as a global.
 function exportModule(name, module) {
 if (global['define'] && global['define']['amd']) {
 global['define'](module);
 } else if (global['exports']) {
 for (var key in module) if (module.hasOwnProperty(key)) {
 global['exports'][key] = module[key];
 }
 } else {
 global[name] = module;
 }
 }
 
 // Export brainfuck module. 
 exportModule('brainfuck', { 
 'run': run,
 'read': function() { throw new Error('"read" function not provided'); },
 'write': function() { throw new Error('"write" function not provided'); }
 });
 
}(this));

Test it out here. I have no specific concerns at this point, I'm just looking for a general review.

The previous version is here. This version takes into suggestions from the review on that version into account:

The previous version is here. This version takes suggestions from that review into account: