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Added comments for some regex used in bindings.

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This commit is contained in:
Nedyalko Nikolov
2015-07-01 10:24:02 +03:00
parent 440e5968f2
commit cff1e8f891
2 changed files with 13 additions and 1 deletions
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3
ui/builder/binding-builder.ts
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@ -1,4 +1,5 @@
var expressionSymbolsRegex = /[ \+\-\*%\?:<>=!\|&\(\)\[\]^~]/;
// regex that contains all symbols applicable for expression used to AI detect an expression.
var expressionSymbolsRegex = /[ \+\-\*%\?:<>=!\|&\(\)\[\]^~]/;
export module bindingConstants {
export var sourceProperty = "sourceProperty";

11
ui/core/bindable.ts
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@ -21,7 +21,12 @@ function onBindingContextChanged(data: dependencyObservable.PropertyChangeData)
}
var contextKey = "context";
// this regex is used to get parameters inside [] for example:
// from $parents['ListView'] will return 'ListView'
// from $parents[1] will return 1
var paramsRegex = /\[\s*(['"])*(\w*)\1\s*\]/;
// this regex is used to search for all instaces of '$parents[]' within an expression
var parentsRegex = /\$parents\s*\[\s*(['"]*)\w*\1\s*\]/g;
var bc = bindingBuilder.bindingConstants;
@ -201,6 +206,12 @@ export class Binding {
}
private prepareExpressionForUpdate(): string {
// this regex is used to create a valid RegExp object from a string that has some special regex symbols like [,(,$ and so on.
// Basically this method replaces all matches of 'source property' in expression with '$newPropertyValue'.
// For example: with an expression similar to:
// text="{{ sourceProperty = $parents['ListView'].test, expression = $parents['ListView'].test + 2}}"
// update expression will be '$newPropertyValue + 2'
// then on expression execution the new value will be taken and target property will be updated with the value of the expression.
var escapeRegex = /[-\/\\^$*+?.()|[\]{}]/g;
var escapedSourceProperty = this.options.sourceProperty.replace(escapeRegex, '\\$&');
var expRegex = new RegExp(escapedSourceProperty, 'g');