>Think I worked it out:
>
>The link function needs to be run pre-link with a priority > 0. i.e:

app.directive('smNumberFormat', ['$filter', function ($filter) {
>            return {
>                restrict: 'A', // only activate on element attribute
>                require: '?ngModel', // get a hold of NgModelController
>                priority:  100,
>                link: {
>                    pre: function (scope, element, attrs, ngModel) {
>                    if (!ngModel) return; // do nothing if no ng-model
>
>                    //Set the default decimal place to zero, if accuracy is not specified
>                    var accuracy = parseInt(attrs.accuracy) || 0;
>                    var stripCommas = attrs.stripCommas || true;
>
>                    ngModel.$render = function () {
>                        return element.val(ngModel.$viewValue);
>                    };
>
>                    var format = function (newValue) {
>                        console.log("Running snNumberFormat formatter");
>                        if (accuracy > 0) {
>                            newValue = parseFloat(newValue);
>                        } else {
>                            newValue = parseInt(newValue);
>                        }
>
>                        //Let's not show any value if it's zero or not a number, so the placeholder text is displayed instead
>                        if (isNaN(newValue)) return undefined;
>
>                        newValue = $filter('number')(newValue, accuracy);
>
>                        if (stripCommas) {
>                            newValue = newValue.split(",").join("");
>                        }
>                        return newValue;
>                    };
>
>                      function bind() {
>                          return ngModel.$formatters.push(function (value) {
>                            return format(value);
>                        });
>                    }
>
>                    bind();
>
>                    element.on('blur', function () {
>                        return element.val(format(ngModel.$viewValue));
>                    });
>                }}

>
> BTW, would you agree that for numberInput we probably don't need to check for actual number, we may just check for the value (could be a string) being a number. If that code would have checked that instead of isNumber function, then I would not have a problem.
>
>Not sure what you mean. If you're using 'type="number"' then angular ensures that the value received by your formatter will be the string value of a valid number.
>If you're not using 'type="number"' then (assuming the model value is a number) then you will receive a number.

I found situation where this fix still produced an error although a different one. I have that html:

 <table id="payInvoicesTable" ng-show="payInvoices" class="table table-bordered table-hover table-list">
                <thead data-search:table-header data-table="payInvoicesTable" data-search="search()">
                </thead>
                <tbody>
                    <tr ng-repeat="result in payInvoices" ng-form="payInvoicesRow">
                        <td>
                            <input type="checkbox" ng-model="result.isToBePaid"
                                   ng-change="payChange(result)" />
                        </td>
                        <td>
                            @*<a href="javascript:void(0);"><span ng-click="drillDown(result.invoice_No)">{{result.invoice_No}}</span></a>*@
                            <a href=""><span ng-click="loadInvoiceView(result.invoice_No)">{{ result.invoice_No }}</span></a>
                        </td>
                        <td>
                            {{result.descrip}}
                        </td>
                        <td>
                            {{result.dateCreated |date: 'medium'}}
                        </td>
                        <td align="right">
                            <span ng-class="{'negative-amount' : result.invoiceBalance < 0}">{{result.invoiceBalance | currency}}</span>
                        </td>
                        <td>
                            <div class="input-group">
                                <span class="input-group-addon">@Labels.currencySymbol</span>
                                <input type="number" name="payment" ng-model="result.payment" id="payment"
                                       ng-disabled="!result.isToBePaid"
                                       ng-class="{'negative-amount' : result.payment < 0}"
                                       min="0"
                                       class="form-control"
                                       data-sm:number placeholder=" 000.00"
                                       data-sm:number-format data-accuracy="2" />
                                <div class="field-validation-error">
                                    <span ng-show="payInvoicesRow.payment.$error.min">Payment should not be negative.</span>
                                </div>
                            </div>
                        </td>
                    </tr>
                </tbody>
                <tfoot>
                    <tr>
                        <td colspan="4">@Labels.pageTotal</td>
                        <td><span ng-class="{'negative-amount': total('invoiceBalance') < 0}">{{total('invoiceBalance')|currency}}</span></td>
                        <td>{{total('payment')|currency}}</td>
                    </tr>
                </tfoot>
            </table>

So, as you can see I have number inside a cell in the table created using ng-repeat directive. Here it's not working. I'll try to remove format from that page and see if the problem will be resolved.